I don't know how many messy videos I've watched where a plastic drop cloth has been placed somewhere to block or catch mess and it winds up falling down or getting pulled away from where it was intended to stay. 99% of the time they used super-thin and super-cheap plastic which wrinkles up, sticks to bodies, and winds up pulling away from wherever it was taped.

An easy thing to do is to purchase vapor barrier seal from a home repair store. It is much thicker than the cheap 'drop cloths' they sell, and can even be hosed off and reused. It's large enough to cover a whole bed and tuck in the corners, or to cover a wading pool completely.

Tucking in the corners? You can't use too much tape. The weight of the mess plus the weight of a human or three will pull on the plastic sheeting, so you had better tape it well if you want it to stay in place.

It's almost a pet peeve of mine when I see a video and the plastic sheeting gets pulled under the models and winds up not doing anything other than creating a scratchy surface for their wamming experience.

Take my advice. Use the thick stuff. Tape it down good. You'll thank me.