Unfortunately Sarah, the cheerleading ditz that she is, used a poor choice of words.
Before he could react, Jon's body shrunk and gained an unusual pinkinsh hue. His body flattened and in the space of a few seconds he was turned into a skimpy pink pair of panties, not unlike the dozens already in Sarah's dresser. The panties were buried in Jon's clothes (with the rock.) As Sarah leaned over to look at what happened the panties leapt out of the pile knocking Sarah on her butt. The panties clung to the front of her shirt and as she reached to grab them they moved again, slithering down her capri pants and swung around her foot. grabbing her other foot with the opposite leghole grabbing her other foot, before she knew it the panties were up her legs and around her waist. Sitting neatly over the panties she put on that morning.
Sarah stood up and picked up the rock. Just then she felt her underwear shift again. It flet like some kind of rodent was in her trousers as she squirmed about for a moment, then she heard a tearing sound and a torn pair of blue panties was ejected from the waistband of her pants by the jealous pink pair.
Of course, all this time Jon really didn't mind, because as per Sarah's wish; he was in her pants, touching her body and most importantly: he wanted to be there! Which could make removing this sentient piece of underwear quite difficult.
