Revving up a lawnmower

A two part sexual act.
The first part of the act consists of forgetting to use a lubricant on Anal Beads before inserting them into anal cavity of an unsuspecting sexual partner.
The second part is simply a quick removal of unlubricated sex toy in a manner similar to revving up a lawnmower, causing severe damage to the sex partner.

Dude, I once knew this goth girl that was into butt stuff. She wanted me to bead her up, but I forgot to use the lubricant and ended up lrevving up a lawnmower