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.
