B Hayes's definitions
Having sex with a girl from behind, and finishing on her ass. After you've finished you use a rubber spatula to evenly distribute the cum on her butt cheeks, as if it were icing on a cake. When this is complete you may stick a candle in her butt hole and light it. Finish off by putting on a birthday party hat and you have successfully completed The Birthday Cake.
"Dude, I gave Steph the birthday cake last night!"
"Oh that's nice of you dude, was it red velvet or...?"
"No dude, I came on her butt and smeared it with a spatula."
"Oh that's nice of you dude, was it red velvet or...?"
"No dude, I came on her butt and smeared it with a spatula."
by B Hayes April 15, 2013
Get the The Birthday Cakemug.