Bill Cosby can explain sex in your 70's, but he cannot comprehend the intelligence of a moth.
That sentence doesn't even begin to show how bizarre the 77-year-old comedian's Monday appearance on The Tonight Show was with host Jimmy Fallon.
For example, Cosby greeted the audience by saying, "We're here! We're here on the Fallon show and we're waiting for the gas pedal and the clutch and the brake... Too many people have hit the deer, and the deer always win. But the ones I don't understand -- I don't understand the intelligence of a moth."
Viewers didn't even have time to let that strange sentence set in before the funnyman was talking about having sex with his 70-year-old wife for his birthday. "The most frightening things that you can hear from your wife on your birthday when you are carrying on ...is to hear her say, 'Keep going,'" he proclaimed.
He then began to repeat himself and instructed Fallon on what to do when he said, "Keep going." Like the rest of the audience, Fallon didn't seem to get it.
It seems nearly every Tonight Show episode has some sort of memorable moment. ET goes inside the power of Jimmy Fallon.