"So, "Coach", ahem, all this Kevin dude did was grab you by your ear lobe like this and you turned into his jockstrap?" you say reaching up and grabbing his ear lobe.
Coach Allen shivers as he feels the changes begin again. He is becoming insubstantial. He pales taking on the coloration of the cotton jockstrap that he will ultimately become.
"Quick, you've got to get out of here before Kevin returns," he gasps then adds hurriedly, "Please take me with you. Put me some place safe."
"I know just the place," you say smugly pinching his ear tighter with one hand, as your other hand works your belt and fly.
Your cargo shorts drop to your ankles revealing that you'd gone commando today. The coach seems a bit confused, but then where else would any guy put a jockstrap. You step out of your shorts, as you feel his body weight rapidly decrease. The coach is now a cross between a cloth puppet and a jockstrap, his human features are still recognizable. You examine his proportions and the opening between his arms and legs and decide which hole to step into. You can feel the warmth of his body as you calf brushes against him. Then you repeat the action with your other foot, and raise him up over your thighs. He's still too big to pull up your cargo shorts comfortably, so you just stand there waiting.
"Heh, shrink-to-fit!" shouts a voice from behind you.
"Oh, no, it's Kevin," gasps the coach in a thin wispy voice.
"Hey, Kev, 'bout time you showed up. I thought you were going to miss all the action," you say snapping your new waist band in place as the coach's transformation completes. You add, "Uh-huh, now that's a snug fit!"