Preferably on xmas eve, whilst having sexual intercourse doggy style with your girl friend, just as your about to climax you sneakily slip it into her ass. When she turns round in shock and horror you pull out and ejaculate all over her face shouting 'Ho,ho, ho' leaving her rosy cheeked with a white beard just like Santa Claus.
Jim: "I pulled Jess at the office xmas party last night; when we got back to my apartment I gave her a Back door Santa as an early xmas present"
Peter: "Sweet"
Peter: "Sweet"
by Studley Ramrod September 6, 2012
by Delray87 December 1, 2011
7-10 split and as the ball careens down the lane, in order to encourage the ball to get the spare you say "back door santa claus"
by dtanger22 August 7, 2010