Man on the Moon
When having sex with a chick and you are doing her from behind, right before you "finish", you take a flag with your name on it and stick it into her ass hole and as you finish you yell out "I'm the man on the moon!".
Guy1:  "Last night I conquered new territory, I took that fine ass home and planted my flag!"  
Guy2:  "Dayam man!  You pulled a man on the moon on her ass!"