We both positioned our respective underwear in front of us - the outer and less intimate surface of the gussets facing towards us - and Dane lifted mine up to his nose first. I followed his lead, applying the outside of his shorts to my nose even though I would have strongly preferred to have done so with the inner lining, and we both took a few gentle sniffs of the material.
To my surprise, almost immediate, I saw through the corner of my eye that Dane's member was starting to twitch to life. It was lengthening in pulses and slowly rising upwards, like an air bed being blown up in short, steady breaths.
Dane seemed oblivious to surges of life that his organ was revealing and sniffed intently at the front of my pants, turning them this way and that to fully explore and appreciate the odour I'd left on the white material.
I took a few sniffs of his but was far less curious about the smell of his cock than he clearly was about mine.
He pulled back and looked over at me, grinning. "This is actually kind of bizarrely interesting!"
I smiled back at him. "I'm a bum man myself, but I can appreciate the appeal of the front."
He took a few more sniffs and then declared, "It's a really masculine smell - a bit pissy but with a sexy whiff to it too - and totally different from the smell of my own dirty underwear."
"Obviously you like it," I observed.
"Yeah... kind of... but not really in an erotic way."
"Your erection would suggest otherwise, Dane."
His expression turned to surprise and, pulling my briefs away from his face, he peered down at the front of his own underwear. His cock had grown large enough to make a pronounced bulge against the crotch, poking upwards like a thick, stubby rod and lifting the material a good few inches towards his stomach. It probably wasn't hard enough to be properly called an erection, but it had grown large enough for him to blush at the sight of his own unwitting arousal.
"Bloody hell, Rob!" he called out. "I didn't even feel that happening!"
I smiled. "It's a bit like what happened when I sniffed yours."
"That's so weird!"
His expression of shock slowly transformed into a stupefied grin.
I was so pleased I'd persuaded him that we should hitch down our trousers. If I'd believed what he'd said, I'd never have guessed that the smell of my cock had had such an invigorating effect on him.
This was proving most hopeful: far better than I'd dared to imagine.
He looked over at the crotch of my underwear and found, to his obvious disappointment, that my own organ was still stubbornly soft.
"The smell of mine isn't having the same effect on you, then, Rob?"
I shrugged. "Like I said, I'm very much a bum man, Dane."
I turned his briefs inside out so that the staining on the inside of the crotch was garishly obvious. As well as several dried yellow rings of tide-marked piss, there was a crusty patch which looked like it had been used to wipe the last few dribbles of a dwindling climax.
I raised the underpants up to my nose and inhaled strongly from the stained material. His sexual odour was eye-wateringly ripe: rich with the sour sting of his youthful pheromones and heavy with the cloying smack of his pubic sweat.
"I think I saw it grow a bit," he laughed, looking at the bulge my large but drooping cock was making against my underwear.
"It's an interesting smell," I conceded, "and I appreciate the fact you've once again left me a dried-on deposit which is rather whiter than the rest..."
He threw me a naughty chuckle just like my son would when I pointed out evidence of a masturbatory impropriety.
"But the best is round the back," I went on. "At least as far as I'm concerned."
He did the same as I'd done: turned my underpants inside out and examined the inner lining of the crotch which my large genitals had spent a day in close confinement. As I'd noticed at the back of the car, unlike his shorts, my briefs were mainly clean save for a few small patches of discolouration where my cock had leaked after taking a pee.
He seemed to like what he saw, though, and smiled and nodded down at the sagging material. I think he was admiring how stretched it was from being cupped around my generous cock and over-ripe bollocks, perhaps feeling a little envious of how much strain I could put on the front of a pair of Calvins.
He raised them up to his nose and took a sniff of the inside of the gusset, searching the lining with his nose to find its most intoxicating spot. Eventually he settled on a small patch down near the stitching around left leg-hole and inhaled from it appreciatively, pressing the material up close to his nostrils to gain the full effect.
That must have been where the tip of my cock had snuggled into the material, I mused; where my foreskin might have retracted a little, rubbing the more odorous exposed head of my cock against the inside of the gusset.
He closed his eyes and sniffed deeply, and I notice his erection throbbing upwards in its appreciation of my secret scent. His fattening cock-head slowly grew to make a thick, round lump against his underwear as he enjoyed the heady fragrance I'd left on my underwear.
I was probably going to get to wank him off, it occurred to me. The way things were going, and given how horny he was getting, I was more than likely going to get to wrap my fingers around his shaft and pump his foreskin back and forth. We'd smile at each other as I masturbated him faster and faster, both of us enjoying the time-honoured ritual of an older man's hand pleasuring the cock of a younger and more virile male. And then we'd laugh together as he reached his climax, and I'd pretend to be disgusted by having his hot, sticky semen all over my fingers and thumb.
That had to be the very least I was going to get to do with him.
All in good time, though; all in good time.
If I pushed things too quickly, the opportunity to wank him off might be all I would get. But if I played things more carefully, I might yet get to enjoy the more exotic activity that I'd mentioned earlier and he hadn't been prude enough to dismiss out of hand.
After he'd savoured the smell of my briefs to the point at which he wasn't able to extract any further scent from them, he put them back down onto his knees and looked over and grinned at me.
"Obviously you enjoyed that," I commented, glancing at his now extremely noticeable, and imposingly thick, erection.
"Just a bit," he chuckled.
"I'm sorry I didn't leave you a more... er... crusty deposit on them, like you did with me."
He shrugged. "I liked what I smelt - any more might have been too much."
I smiled and turned his briefs over.
"And now for the back," I said, looking down at the strip of material which must have nuzzled into the crack of his arse. It was discoloured in places but not as much as I'd expected.
He looked over at them and winced at the state they were in. "Are you sure you don't want to reconsider, mate? I'm normally much cleaner in my habits."
I shook my head. "Happens to us all, Dane. You should see some my son's underwear when he brings his laundry home after a term at university. Yours are almost spotless by comparison."
"At least you're not tempted to sniff his, though," he said with a laugh.
"I can smell it quite unmistakably without having to sniff it," I chuckled back.
I raised Dane's briefs up to my nose and tentatively inhaled from the stained material. As I'd expected, the smell was strong but not offensive. It was undeniably crude and fiercely anal in its unbridled intensity, but there was, combined with that coarse, effluvious odour, a much more exciting and erotic undertone: a sneak preview of this young lad's sexual aroma if he were to indulge me in the most intimate way he could.
I smiled at the thought and felt my cock starting to stir.
Yes, this was the smell I would experience if I was buggering Dane with him bending over in front of me. It was the smell that would fill the car if we were to squat on the back seat together and I was to use his arse so fast and so hard that our pendulous knackers would whack together underneath us.
My cock responded to such musings in the only way it could. Dane laughed at the speed at which it lengthened and thickened, forcing my briefs upwards as it hardened inside them and pushing itself free from where it had been slumbering against my scrotum.
"My bum really gets you going," he grinned.
I smiled back at him, thankful that he hadn't been able to read my thoughts. The picture I'd had in my mind might really have freaked him out.
He peered down at my developing erection through the cotton of my briefs, marvelling at its size. Then he announced, with undisguised admiration, "You're really well-hung, Rob."
"I wish my wife could still get me going as much as these do," I quipped.
He kept staring at it, grinning with wonder, and I turned a little more towards him and pushed my hips outwards so that he could better appreciate how large my growing cock was and how abundantly-filled my bulging balls were.
He looked up at me and smirked naughtily, and for a second I thought he was going to reach out and pull my cock out from my underwear. I'd have liked that, and would have urged him to start masturbating me: the two of us chuckling together as his fist pumped up and down my grateful shaft; gasping as my seed squirted over the windscreen and dashboard.
But if he had been about to reach out and stroke me, he lost his nerve and pulled back, and contented himself with just admiring the view I was presenting him with.
"Why don't you have sniff of my bum?" I asked him when it had become clear he wasn't going to grope me.
He looked up at me, momentarily confused, and I reminded him that I meant on the back of my discarded underwear.
"Oh, right, yeah!" he laughed.
He turned my briefs over so that the rear gusset was facing outwards and inspected them to find they were largely clean.
"You might find that it's not as bad as you're probably expecting," I told him.
"I might lose this, though," he muttered, gesturing towards his own thick, stubby erection pushing the front of his shorts upwards.
