"The human trashcan!" Dixie jeered. "At least he's good for SOMETHING."
Trixie had kept a grip on your briefs. "Yeah," she rejoined, "just got to compact it a bit." You winced as she swatted your rear, mashing up the food and squashing it against you.
[Pull your briefs snug and spank the seat of them 5 times.]
Seeing that you obviously weren't going to put up a fight, Trixie grinned impishly and hiked the waistband up your back. A bit of food slipped out your briefs to splat on the pavement.
[Pull your undies into a messy wedgie.]
"Okay -- DOWN, boy!" She shoved you into a chair. As your butt rammed into the hard seat, you couldn't hold back a yelp. The mess in your undies squished up your crack.