Another "lovely" trigger from Minx:

When I arrived home last night, I dropped my things on the counter and went to my comfy seat in the living room to watch some DVDs while waiting for Mandy. The moment my butt hit the leather, my jeans (which are normally pretty baggy) suddenly tightened around my legs and crotch, and turned into black leather. Worse yet, some kind of invisible force started rubbing me at the crotch area, and I "grew" rather impressively. Enough so that, in fact, my pants couldn't "contain" me, and Mr. Jaycee Junior poked his turgid head above my belt.

And that's when Mandy came in through the door, staring at her (rather humiliated) boyfriend. Worse yet, she was accompanied by her workmate Renee, who (I would learn later) literally invited herself to our place for drinks.