When a male ejaculates into his hand. He then proceeds to rub the semen onto the testicle hair and then runs the testicle hair over the woman's face. Hence, giving her the dirty paintbrush
I can't go out tonight... My wife wants to try the dirty paintbrush and I can't turn it down!
When a man has anal sex with a woman, then uses the remaining excrement on his dick to paint on the woman's back.
Clarke: I brought Suz over last week and we got a little frisky.
JP: What'd you guys do?
Clarke: Well, I fucked her in the ass, then used the leftover shit on my dick to paint on her back. We called it the dirty paintbrush.
JP: That's fuckingdisgusting
when you're holding up your phone and making faces at it, as though you are taking a selfie, but you're really taking a picture of the person across from you or the wall or anything else that seems interesting but you don't want to be caught dead taking a picture of.
This action is often made more convincing by wiggling the eyebrows or opening the mouth, to pretend you're trying to get a Snapchat filter to work.
FRIEND A: "Did you just take a stealthie of me?"
FRIEND B (turning phone around): "no I was just using snapchat's new filter, see?"