A synonym for the anus. Used when discussing anal sex. Was popularized by Howard Stern on terrestrial radio as a way of avoiding censorship and to avoid FCC fines.
Guy 1: So how many inputs is she? Does she do 3rd input?

Guy 2: Yeah, she does all 3 inputs. She doesn't go for 3rd input very often though.
by Sparisi1122 November 12, 2010
Get the 3rd Input mug.