Similiar to a wet willy, you take your finger, stick it in your mouth, then shove it up someones rear and swirl it around a few times. Then shout: "WET RUFUS!"
"Then she bent over in her mini-skirt and I saw that she had no panties, so i licked my fingerand gave her a sloppy wet rufus!"
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