The day in which no matter the excuse, your girlfriend permits you the opportunity for anal sex. Fortunately for the men this is a fact!! Ref:-The laws of co-habitation, 1883- mcMiller, Brian. Book 3 chapter 4, section 69.
IE: Jeff- " hey honey guess what day it is?"
Random hot chick- "hump day?"
Jeff- " kinda! It's my b-day which includes birthday anal, plz adopt the position."
Random hot chick- "hump day?"
Jeff- " kinda! It's my b-day which includes birthday anal, plz adopt the position."
by Rules of engagement December 3, 2013
When your so excited that it's your birthday that when you go to blow out the candles you shit your pants.
Shane: Ryan had an anal birthday last week
Jordon: How do you know?
Shane: There was choclait frosting in his pants
Jordon: How do you know?
Shane: There was choclait frosting in his pants
by Not So Happy Birthday February 20, 2011