butthole shielding

When you squeeze your asscheeks together to protect your butthole. A person who executes this act is likely doing it for one of two reasons:

1) To hold in a turd when you really have to take a shit
2) Protect yourself from butt rape

Person 1: Why is Carly walking so funny? I bet she had anal for the first time last night and her asshole hurts! WHORE!
Person 2: It looks like she is actually butthole shielding. I bet she has diarrhea.