Originally a song by Cannibal Corpse, it has also become what is known as one of the most annoying memes ever on UG (Ultimate-Guitar) in the message forums.
Person A: Hey Pit, whats a good song to learn how to play onguitar for my girlfriend?
Person B: I Cum Blood
By Margarete
Huh? Yeah I Cummed In Her!
The act of saying you banged some skeezer when you actually may not have; something a Doofis might say.