sponge painting
When a girl is on her period and gets the blood on her overgrown bush and then uses the blood to "sponge paint" on her partner.
Guy 1: Bro, why does it look like Helen Keller tried to paint a Bob Ross mural on your back?
Guy 2: Aw shit, Lafonda was on the rag last night, that bitch must've started sponge painting me after I came home blacked out.