Yelping in disbelief, you rush out of the building into an adjoining alley. There you halt and yank your newgrown appendage forward to look at it. "How the hell have I grown a tail?!!"
Though not as long, hairy or tufted as those of the boys in the pool hall, it's still pretty obvious - about twelve inches in length and coated with a soft brown fuzz... Tentatively, you trace your hand back along the tail to its root, jutting out from your jean cutoffs. It's so thick... Fascinated, you finger the white cotton sleeve which encases the first inch of it. So that's what happens to boxers when you punch a tail through them!
Releasing your tail, you suddenly realize you can sense it back there. Not just the weight of it, but also its length and flexibility. And you can move it too... While you were examining it, a set of new muscles came into play and now, though it feels weird to do so, you can make the tail twitch from side to side. As it does, its root rubs against the torn fabric of your cutoffs and boxer shorts.
Unaccountably, you grin. Though it feels odd to have a tail, it's also kind of neat. Like having a second, unconfined, wonderfully mobile cock!
Taking hold of the tuftless tip of your tail, you feed it into your right pocket and push it down as far as it will go. Then, having checked your ears for any sign of donkey ears (for the moment missing), you haul down your T-shirt to hide the rest of your tail and leave the alley for the bar next door...