The act of having sexual intercourse with someone while they are sleeping or passed out. Despite hearing many reports of successful fornication the prey will usually wake up and have the predator thrown in jail.
Flip- "Dude! Alexa's passed out in my room right now, Im about to pull the Sleeper Creeper on her. You wanna come over and take turns?"
Skip- "Naw, Ill pass this time. Besides I smashed that months ago."