Sadie gets a sandy (Patreon)

"Sandy (also known as a "wedgie on the beach"): An ultimate prank involving rubbing down a victim's buttcrack thoroughly with sand, immediatley followed by administering an especially hard wedgie deep into their butt. The sand creates an intensely coarse and dry friction in the buttcrack, the likes of which are beyond comprehension. It is desire you avoid receiving a sandy, it will destroy your buttcrack."

...poor Sadie. lol