Slang; origin, Dublin's southside. Involves getting so shitfaced that you completely forget about how you creampie surprised that lucky person the night before, until reminded about it later on the next day.
"Holy shit, I can't believe I fucked up again last night and gave that ugly bitch a Blackout City Creampie Surprise, let's hope she's clean."
by Sconson October 26, 2009