Maybe Bex could put Tiff in a tickle machine with rotary spinning pink ostrich feather static dusters tickling Tiff on her pelvis, upper belly, armpits, and feet while Bex takes notes on Tiff's agonized laughter and pleas for Bex to stop or else "I'LL GO MAD"! Bex could be dressed in a lab coat for good measure. It would all be for science class project. ^_~
Better yet, Tiff could be placed in King Kong peril (tied spread eagle to an altar in her cheerleader outfit and gagged) with Bex waving goodbye (obviously responsible for putting Tiff on the altar) as roars are heard in the distance. Oh the possibilities. :wub 😉 😀