A few months ago I met a guy called Edward and it turned out that, among his varied and chequered past, he'd been divorced and has a son in his late teens, just like me.
His lad is called Ashley; he's eighteen and at university in Sheffield. My son is Jake who's nineteen and at Leeds.
Edward is physically much larger and stronger than me; something I always enjoy in a man when we get to the bedroom. He's tall and muscular and could easily handle himself in a fight, and I wasn't too surprised when I first took his shirt off to find a scattering of tattoos across his arms, chest and back.
He and I aren't the sort of men who would naturally form a friendship and I'm sure that if Edward hadn't spent eighteen months in prison for tax fraud, we would barely have registered on each other's radar. But having developed a liking for using cellmate's obligingly-offered rump when he'd been inside, he'd emerged from his incarceration eager to continue his newly-discovered pastime.
Unfortunately for Edward, it turned out his girlfriend wasn't as willing as his cellmate to satisfy his craving for doggy-style anal. Fortunately for me, he sought to fill the breach by signing up to a male cruising site to find other men who would be willing recipients.
So that's how we met. Kind of cute, really.
It was during the lull between two very strenuous sessions - Edward inexhaustibly pounding in and out of my upturned behind - that we started chatting about our sons.
We were lying on his bed, both naked of course and with our cocks exploiting a brief opportunity to soften slightly, and I happened to mention that Jake would be coming to stay over that weekend.
"Nice," Edward muttered, well aware of how much I enjoy spending time with my son.
"It is nice, yeah," I replied. "Apart from all the bags of dirty laundry he'll bring back with him."
Edward glanced over at me and then asked, completely out of the blue, "Do you ever stash away any of his underwear to have a sneaky sniff of?"
I smiled. I liked the way he would just casually come out with deeply personal questions like this one.
"No," I replied. "But I often admire his butt when he struts about with barely a stitch on, as he so often does."
We sat for a few moments before I asked in return, "I take it, from the question, that you enjoy a sniff of Ashley's underwear from time to time?"
He nodded and said, a touch defensively, "I don't see anything wrong in it."
I nodded back. Neither did I.
"I mean, if he's going to bring so many bags of laundry home with him from uni," he explained, "it's only fair that I get something out of having to wash it and dry it for him."
I chuckled. "Don't worry, Edward - I'm no angel! I'm certainly in no position to judge. Which... er... part do you usually sniff?"
He grinned over at me. "Oh, come on, Rob! Like you have to ask! I like bum sex, mate - that's why you're here! Which part of his skanky shorts do you think I get my nose stuck into?!"
I laughed back at him. "So I take it he's a bit whiffy back there?"
"A bit whiffy?" Edward chortled. "You have no idea, mate! Every single pair absolutely reeks of his arse! That's why I do it... it's like... skidmark city!"
"Do you jerk off when you're sniffing them?"
"Of course I do!" he grinned. "I pick all his dirty boxers out from the black bags of laundry he brings back with him and keep a little stockpile of the... er... more fragrant ones at the bottom of my wardrobe. Then I work my way through them night after night, whacking off with his bum stink covering my face, imagining my dick was hammering away at a lovely round arse!"
"Ashley's arse?" I asked.
His head swung round pissed off at the suggestion of that. "Of course not! Jesus, mate! Like I'd get off thinking about shagging my son! What the fuck do you think I am?"
I smiled in an attempt to placate him. "I only asked, Edward! You didn't make it clear whose bum you were imagining... er... hammering away at."
"Carol's!" he called out; Carol being the anally-reluctant girlfriend. "Or yours," he added as an after-thought. "Yeah, sometimes yours."
"Aw that's so sweet," I laughed, knowing he'd be aware that I was being sarcastic.
"It helps fuel a good wank," he explained, "having a pair of dirty pants to sniff on. You can just about believe you're banging someone's backdoor for real, the stink on the back of the shorts is so similar to the smell you get when you're doing it butt-style!"
"Why Ashley's though? I mean, why don't you sniff your own briefs when you need some 'fuel'?"
His own underwear was, as I'd often remarked, rather wonderfully odorous: especially right behind his big hefty balls where the sweat from his arse-crack would make for some most stimulating sniffing. I'd spent goodness knows how long with my nose wedged in the back of his briefs, usually with Edward grinding his firm, meaty buttocks vigorously against my face.
"I dunno about you, but it's not as horny when it's your own," he replied. "There's something really sexy about someone else's smells. That's probably why I found I liked anal so much when I tried it that first time with Derek."
Derek had been the obliging cellmate. Their regular sojourns had started up after several nights of glancing over at each other struggling to masturbate in their bunks after lock-down. Perhaps inspired by the sounds of other men's furtive couplings from along the corridor, Derek had got on his bunk bending forwards on all fours and, as if further clarification were needed, had pulled down the back of his Y-fronts to expose his pale flabby arse. Edward had seized the opportunity and had tottered across to take up his place behind him, pushing his knees between his buddy's shins and lining his cock up against the thick clumps of matted hair bristling from the odorous crack that was being so generously offered.
After a few terse shoves and a good deal of grunting and gasping from Derek, the two of them had quickly developed a rapid, forceful rhythm of hips against buttocks, rutting noisily together in time with the quickening thumping of the other men on their corridor.