The situation one faces if offered sex when one's poopchute is in a state of less-than-optimal hygiene. This may be due to splatter ass, lack of access to bathing facilities, or just plain laziness. The risks are to accept the sex and run the risk of being thought a skank or dirtball, or to turn down the sex even though you might avoid detection of your filthy fudgepipe.
Named for Beavis's alter ego, Cornholio, who always needs TP for his bunghole.
I had just gotten back from a camping trip when my buddy's hot sister walked up the driveway and started coming on to me. Having gone three days without a bath, using only leaves for toilet paper, I thus experienced Cornholio's Dilemma.