The-Bill is a sexual position in which one person inserts a fist into the anus and inserts the other fist into the mouth and lifts the other person over their head shouting "THE-BILL!"
When you're drugged, and something happens to your body that you have no memory of, but definitely happened.
"How was your colonoscopy?"
"I don't know, it was The Bill Cosby Experience... I was awake. Then I wasn't. I woke up. Something was in my ass. But I don't know for certain."