The guy says, "No no no, it's a tame alligator. I'll prove it to you."
He picks up the alligator and puts it on the bar. Then he unzips his pants, pulls out his package and sticks it in the alligator's mouth. The alligator just keeps his mouth open. After about 5 minutes, he pulls it out of the alligator's mouth and zips up his pants and says, "See, I told you it was a tame alligator. Anybody else want to try it?"
The drunk down at the end of the bar says, "Yah, I'd like to try it but I don't think I can hold my mouth open that long!"