The final symbolic vestige of integrity and dignity that people have before they allow their "backyard" to become a playground for others' body parts, various tools, and terrified rodents. It's the anal maidenhead.
Muriel: Gee Whiz, Cindy! Sit down! You're acting like you have ants in your pants!
Cindy: Oh, Muriel! I let Salvatore do things to me last night and I can't sit down. It's horrible!
Muriel: So he finally took your heine hymen! He'll never respect you again and probably told all the fellas by now. At least that's what he did to me...