When you take a massive shit and go to wipe, but you don't realize your Hulk-like strength and destroy the toilet paper in your hand. Then you continue to wipe your ass with your bare hand.
Oh man, I was in the bathroom the other day and totally had to beastwipe. My hand still fucking smells.
Boys who enjoy yaoi (a genre in Japan that contains sexual and/or romantic relations between two men); literally translates to "rotten boy"; corresponding female : fujoshi