When a male with a smaller penis inserts his genitals into the urethra of another man's much larger penis and proceeds to thrust in and out, thus resulting in penis fucking.
Big Dick: unnh my dick wont fit into your ass, wanna just do some penis fucking tonight?
Small Dick: sure (inserts penis into other mans penis) unh yeah feels like a pussy
Big Dick: mmmm fuck yeah, hard and deep Small Dick: I'm cumming! (shoots a huge load into the larger penis)
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