Over the coming days, I realised I was noticing other men's backsides in the same way that I would have previously noticed women's breasts. They were no longer just innocuous mounds of flesh which they sat on, and did other less palatable things with; they were suddenly extremely captivating, from their different shapes and sizes, to the varied hemlines made by their underwear when they bent over.

I work in engineering – still a largely male-dominated field – and abruptly the forest of trouser-clad arses which had surrounded me for years without capturing the merest sliver of my attention, were the subjects of my fascination and fantasies.

Some of the guys – especially the younger ones – wore tight-fitting trousers showing their firm and round backsides off beautifully. I found myself in the odd position of envying the cushioned seats of their office chairs for being able to spend most of each day having such magnificent buttocks pressing so intimately against them. How good it would be to have such pert cheeks perched on top of me for so long; how exciting to furtively nuzzle between them as they bore down on me.

I wondered why I had never previously noticed the appeal of my fellow men's backsides. They were so ripe and round – so delicious-looking, and, I had to admit it, so crying out to have a mouth to feast on them. I would spend hours daydreaming about doing to them the things I had seen on the internet – hitching their trousers and underwear down and teasing their hairy clefts with my tongue, revelling in their unique tastes and smells.

I could never remember developing erections at work before but now I seemed to spend most of each day in a state of prominent arousal. I took to wearing a jacket to help conceal the activity going on in my trousers which my underwear was unable to contain and would try to direct my hard-on, whenever it was possible to do so, upwards beneath my belt so that it was flat against my stomach. In spite of such precautions, I'm pretty sure that some of my workmates noticed that my trousers would sometimes tent outwards at the crotch: I only hoped that they didn't notice that this seemed to happen directly after I'd been staring at their bulging backsides.

When erections became particularly problematic, I would retreat to the gents at the end of my corridor so I could attend to myself as discreetly as it was possible to do in a communal lavatory. Visiting the gents had the added bonus that I would occasionally get to see an exposed arse as some men chose to use the urinal with their trousers and underwear pulled down around their thighs. I'd never understood why they would do that – I was far too shy even to pull my cock out through my fly at the urinal and would always make a beeline for the privacy of the cubicles – but what had previously struck me as a rather exhibitionistic way of urinating was now a further source of interest and excitement.

I'd loiter at the washbasins, watching my co-workers standing at the urinals through the mirror as I cleaned my hands so thoroughly it was like I had a compulsive disorder. Some of them would glare over at me, aware that I was looking at them, and I would hurriedly finish up and leave the gents. But mostly they'd be oblivious to my interest as they stood and peed, allowing my eyes to feast on their exposed behinds and my cock to throb in my trousers. Flabby or muscular, hairy or smooth, round or elongated – all of them fascinated me and made me yearn to press my face into them so that my tongue could tickle their pert little holes.

One guy from the third floor – a young guy called Jason who was on the design team – would hitch his trousers down around his thighs but leave his underpants pulled up and covering his bum. He wore tightly fitting briefs of various colours, which beautifully cupped the paired orbs of his buttocks and burrowed alluringly upwards into the deep valley between them. He'd stand and urinate, either unaware or unconcerned that he was the subject of my spellbound gaze, as I focussed in on where the material was riding up between his cheeks, wondering how often it would brush across his hot, pink ring and how much of his rich, earthy scent would be clinging to the fabric.

How exciting would it feel to push my nose into the back of his briefs and sniff his day's odours? How arousing would he smell back there, just above the tops of his legs where the sweatiness seeping back from his balls would give way to something altogether more personal? And how erotic would it be to unpeel his briefs from his cheeks to compare the subtle fragrance he'd transferred to the material with the more salacious flavour of its naked source?

After my colleagues had fastened up their clothing and returned to work, I'd duck into a cubicle and release my excitement into a wad of toilet paper, hoping that the noise of other toilets flushing would conceal the thumping rhythm of my fist and that whoever came in after me wouldn't be able to smell the strong seminal odour which I left behind. Then I'd return to my desk with a cock that was mercifully softened but a conscience that was plagued with guilt about where my thoughts had strayed to bring that about.

===

"Oh, bugger."

One of the toner cartridges inside the printer in my office had jammed. The printer is under my desk which makes it awkward to get to and difficult to see inside of it when things go wrong and so, try as I might, I couldn't release the cartridge from the mechanism which had trapped it.

Eventually I called IT support and they sent Bradley, one of their technicians, down to help me.

Bradley hadn't been working at the company long. He was a skinny guy in his mid-twenties whose face always seemed to be bristled with a growth of stubble in spite of the fact he probably shaved every day. His hair was receding quite noticeably and he kept it clipped very short like a lot of men his age do when they find themselves going bald prematurely. He'd always struck me as being a very blokeish guy; one of the lads with a pint in his hand in the pub after work and a player in the Friday evening five-a-side league.

We went through the usual small-talk that we always did when an IT mishap brought him to my office. He wasn't big on conversation but he was quick to let me know, with a gush of pride which made him seem rather endearing, that his girlfriend was pregnant.

"That's great," I said, smiling to conceal my impatience at getting my printer working again.

"Yeah," he said, beaming broadly. "We're both over the moon, to be honest."

I wanted to curtail things with a "Well anyway..." and move him onto the matter of the printer, but he clearly wanted to talk about what he saw as his impressive accomplishment.

So I asked, "Well... er... when's it due?"

"In the Spring... which gives us time to get a place together. Somewhere for the three of us."

He looked at me expectantly and I realised I was supposed to grin inanely and coo something about it being so sweet. Feeling irritated with myself, I dutifully did so.

After a bit more obligatory back-and-forth about the foetus, Bradley finally turned his attention to the printer.

He peered at it in the gloom under my desk.

I said, stating the obvious, "It's a bit difficult to see how it's become jammed."

"Is it possible to get the printer out from under the desk?"

I shook my head. "Not without a lot of faff unplugging things and fiddling with cables."

He unclipped a leather pouch from his belt and unfurled it to reveal a set of small screwdrivers and other tools. Among them was a slim torch.

"Et voila!" he said, switching it on, with an expectant smirk that made him look as if he thought I would be impressed by his use of French.

Having failed to illicit a response, he crouched down on all fours and leaned forwards to shine his torch into the bowels of my printer. His backside stuck out from under my desk, looking a bit scrawny pressed outwards against his black work trousers but no less appealing for it. His cheeks betrayed the telltale hemline of his briefs, pointing downwards like a chevron signposting the puckered prize nestling between his legs.

"Keep your eye on the screen," he called out.

I recoiled a little, fearing that he'd caught me peering at his bum, but realised he was too absorbed in looking at the printer to have noticed my interest. He just wanted me to see if whatever it was he was doing was having any effect on-screen, which it wasn't.

"No response yet," I replied.

I looked back at his bum sticking out as he kneeled forwards on all fours. In spite of how skinny it was, I was still fascinated by the deep crack opening up between his buttocks as he leaned further forwards and wondered what it would be like to press my face into it. Would I be able to smell the same enticing scent that had so mesmerised me when I'd been underneath Guy? Would it have the same effect on me, even if I was sniffing it through his clothing?

My cock began to lengthen in my boxer shorts and I put my hand in my pocket to prevent it from making an obvious lump in my trousers.

"Is anything popping up now?" he asked from beneath my desk.

"Er... nothing on the screen," I muttered.

He repositioned himself and opened his legs a little wider, pushing his bum out further as he strained to access the printer. His crack was splayed invitingly open and I stared at it, feeling my cock slowly hardening against my hand at the thought of what lay just beneath the material of his trousers and underwear.

He called out, "Do you want get down behind me?"

I knew what he meant but the image which his question had presented made my cock twitch and I felt a dribble of liquid ooze out from its slit. Taking my hand out of my pocket and aware that I was sporting a thickening rod across one leg of my trousers, I knelt down behind him and peered over his back to try and see what he was doing. My face was level with his arse but I kept it a respectable distance away from it.

He looked back at me over his shoulder and said, "I thought you'd want to know how to do this – save you time if it happens again."

I nodded. "Very helpful, yes."

He added, "You're gonna have to lean forward a bit... this is quite fiddly."

I moved forwards a little, my face homing in on the splayed buttocks he was presenting to me.

He smiled at me and teased, "I'll try not to get my bum in your face!"

My cock lengthened again and I could feel the thickening shaft being squeezed by the leg of my trousers. I smiled back and, trying to appear casual, said, "Don't worry about it. I've been around the block a few times..."

I wasn't sure what I meant by that last statement, but he grinned as if it somehow made sense and turned back to the misbehaving printer.

He said, "Your problem's with the feeder mechanism... the delivery unit is misaligned."

I muttered something to suggest I might be vaguely interested in whatever it was he was talking about and directed my attention to his backside.

This had turned out to be something of an opportunity.

He kept prattling on, peppering what he was saying with a wide array printer-related vocabulary which I neither understood nor had any interest in, while I studied his arse. His buttocks seemed long and thin and oddly feminine but it may have been that he had his trousers hitched up a bit high. Where the black material had ridden up between his cheeks was no doubt chafing his briefs against his crack. There was a conspicuous pair of bulges between his legs where his nuts were pressing up against the material. They must be nicely plump, I mused, and from the way he'd managed to fertilise his girlfriend so quickly, the liquid they produced was clearly vigorously potent.

He turned back to me and said, "Get a bit closer. I promise I won't fart!"

I smiled. Yeah, I'd definitely draw the line there.

I moved further towards him, my chin now almost touching his backside as I pretended to strain to see what he was doing inside the printer. Merely being in this position, with my face so close to another man's arse, was making my cock harden to full size. It was confined by the position it was in inside my boxer shorts and the fat bulbous head of it felt like it was trying to tear through the material as it expanded.

I asked, "So can you get it to budge?"

He muttered about unclipping something first and told me to watch carefully. As he leaned forwards to do whatever it was he was doing, he moved his arse slightly towards me so that the crack between his buttocks where his trousers had ridden up was now level with my nose.

I gently pressed my nose between his bum cheeks, inhaling the smell of his splayed arse crack. Instead of the pungent whiff I'd been hoping for, all I got was the sanitary perfume of washing powder from the material of his trousers. It was a Monday – they would likely have been washed over the weekend and fresh on this morning.

Oh, bugger.

I moved my nose further down, towards the spot where his arsehole was likely to be, hoping for at least a suggestion of something more natural. My cock was throbbing in anticipation, painfully struggling to straighten in the cramped space it was in. My foreskin had retracted, exposing the pink sensitive head of it to the coarse material of my boxer shorts.

I pressed my nose into his crack, right where his hot little ring would be and –

Somebody coughed behind me.

I leapt up, banging my head noisily and rather painfully against the underside of my desk in my haste. Reeling, I lurched backwards and then, using my chair to help me, staggered to my feet.

In front of me was a guy I vaguely knew from the accounts department. He was tall and well-built, with a large muscular chest and a good head of black hair. I seemed to think he was called Cameron.

He was staring at me, his expression inscrutable.

I muttered, rubbing my sore head, "Sorry... I was just... he's fixing my printer."

He said, in a voice as impassive as his face, "I brought you some product specifications to check through."

"Oh right. Thanks."

He put them down on my desk.

Then he peered down at my crotch. And stared at it pointedly.

I realised that my erection was obvious, tenting the front of my trousers in an unmistakable prominent rod. Flushing with embarrassment, I covered my excitement with my hand.

"Sorry... I... er..."

Cameron – if that was his name – looked back up to my face, his expression still impenetrable.

Bradley's voice called out from beneath my desk, "You might want to see this, Rob! I think I've got it!" Whatever he was fiddling with made a noise like a cartoon spring.

Cameron glanced down at the source of the voice and then returned his gaze to me. "Well, I'll let you get back to whatever it was you were doing."

I muttered, "Yeah."

He added, with perhaps the merest suggestion of humour, "Enjoy."

And he turned and left us to it.

I didn't get to sample whatever delights might have been lurking in Bradley's arse-crack behind the strong smell of washing powder. I watched him release the cartridge, not really taking in what he was doing but instead replaying what had just happened in my mind to try and fathom out how much Cameron might have seen and what he might do about it.

I spent the rest of the day – most of that week, actually – waiting to be called to my manager's office to be told that sexual harassment charges were being brought against me. I was ready with my incredulous laugh and my outraged disbelief at what I was being accused of. "Sniffing a man's backside!?" I was ready to throw back at them derisively. "Bradley the IT guy!? Is this some kind of joke? Is it April Fools' or something?"

But no call came.

Meanwhile, I did a bit of discreet research into Cameron. That was indeed his name – his full name was Cameron Waterhouse – and he was married with a couple of kids. He had a reputation as a safe, reliable pair of hands and of being very sociable although a little on the boring side.

The next time I saw him was in the corridor when he walked straight past me without even seeming to notice me. I was unable to stop myself blushing, of course, but Cameron seemed completely unaware of me.

I wondered if perhaps I'd been mistaken and he hadn't seen what I was doing to Bradley's arse. Or, if he had seen where my nose had been headed, maybe he couldn't believe it – after all, it was widely known in the office that I'd been married for nearly a decade and having my face stuck into the male IT technician's backside wouldn't be a likely scenario for me to get myself into.

He'd seen my erection – that much was unfortunately true. I couldn't pretend that he hadn't – my cock is far too large to pass off as a stray wallet or displaced mobile phone. The thick and curving protrusion it had formed in my trousers when I'd stood up had made it explicitly clear that he was looking at my aroused penis – he could probably see the engorged head of it throbbing. Maybe it had been that which had stunned him rather than the activity which had been going on under the desk. And for all it was embarrassing to have been caught with an erection at work, these things must happen occasionally even in a mostly-male workplace and – let's face it – I hadn't actually done anything wrong.

So I figured I wouldn't hear anything further from Cameron.

===

During the weeks which followed, I stole every opportunity I could to pore over the wealth of information about rimming on the internet and, of course, to study even more intently the pictures available.

From the stories I read, it seemed that the route I had taken, from a reluctant blowjob to help out a desperate friend to an accidental discovery of illicit treasures lurking behind his balls, was the most common way that men had found that they had a taste for their fellow men's backsides. I was almost disappointed that my introduction to rimming seemed so unremarkable.

There was, however, a sprinkling of more interesting stories of discovery. In one case a young-sounding guy had been helping his friend climb over a high wall and had ended up, after his friend slipped, with his face buried in his mate's bum. In another, a similar position had been stumbled upon by two drunken students during a game of Twister. The confines of tents provided opportunities for others, with the claustrophobic scrambling around to remove and pull on clothes leading to some fortuitous arse-in-face moments. And a bet between two rugby players had ended up with one of them being made to kiss his mate's arse in the changing rooms after a game to much hilarity from the team when the guy doing the kissing had ended up with a prominent bulge in his jockstrap.

While some men said they preferred to rim a freshly-soaped and clean-shaven backside, the majority, like me, admitted to being excited by its natural hairiness and its own inherent smells and tastes. "I expected it be gross but was amazed how electrified and aroused the funky smell of him made me feel," one man wrote, succinctly capturing my own experience. Another explained that "the sight of another bloke's hairy arse would, just a while ago, have been something I'd have been disgusted by. Now I want to get in there, right between his cheeks, and just a whiff of that manly bum smell gets me hard every time." Quite.

Gleaning any sort of clue as why this might be the case – and it did seem to be the case among a wide swathe of men – proved to be perplexingly difficult. Theories abounded but none stood out as the most convincing. Some men pointed out that we all have a homosexual aspect to our sexualities and suggested that, as male genitals hold so little attraction for us as predominantly straight men, we were channelling these feelings towards something which was more rounded and feminine. Others commented, perhaps more plausibly, that the pleasures of rimming were a throwback from an earlier era of humanity, when grooming between primitive men formed an important social function. Supporting evidence for the ideas expressed was scantily vague, however, and it seemed that nobody really had any credible clue as to why same-sex rimming was, for some of us, so irresistibly attractive.
A few men seemed to see rimming as a precursor to penile penetration; a moistening of the rectum in preparation for mounting the other man. That idea hadn't occurred to me and at first I rejected it as something which would not interest me. I really could not imagine myself buggering another man – putting my penis into such a squalid area seemed a distinct turn-off and I didn't think I could maintain an erection long enough to successfully climax back there. But having said that, just a few weeks earlier I would not have imagined myself capable of doing what I had done and had so enjoyed; would not have dreamt that I would be trawling websites such as these.

I discovered that it was possible to watch movies showing men rimming each other for free. There was a huge variety of material showing men engaged in a broad spectrum of sexual activities with one another, from mutual masturbation through to anal penetration in its many guises. Although I watched quite a few of them pertaining to be 'hardcore', I didn't find them nearly as arousing as those which cast men's tongues and arses so beautifully together in the lead roles.

Of the rimming videos I had many favourites, but the one I most frequently returned to had two men squatting on a bed, back to back, with their legs wide open and their balls swinging pendulously. A third guy was beneath them, his tongue outstretched, licking first one man's squatting arse and then the other. How I envied him: poised beneath not one but two magnificent backsides, feasting on their different flavours and relishing their different smells. All three men were erect and the different sizes and shapes of their excited cocks added an extra layer to my fascination with this video: one of the men had a small stubby dick which I found quite cute; another's was longer but thinner with a graceful curve to its shaft. The third – the guy lying on his back – was built rather like me with a long, thick cock and a very prominent pair of nuts; unlike me he showed no self-consciousness about his size and I admired the way he flaunted his excitement and kneaded his ample bollocks while his mouth got to work on his friends' arseholes.

When Jake was out of the house, I masturbated frantically in front of pictures and movies of other men doing what I myself had enjoyed so much. And when he was at home, I found ways of doing it more discreetly just as I had on that first night. I dreaded him catching me pleasuring myself in – what would probably seem to him – indefensibly sordid circumstances, but the urge to explore the wealth of material which was out there was simply too powerful to resist.

Friday evenings were my best opportunity to trawl the web because Jake often went over to stay over with his mum. I tried not to think about how my ex-wife would react if she saw me like that: hunched with my trousers around my ankles noisily whacking off in front of images of men licking other men's splayed arses.

At least she couldn't sneer her favourite put-down: "Predictable as ever, Robert."