Every teacher, ever, has had a student who's talked so much that this has been tempting. If they say they haven't, they're lying.
I've had several students who have put tape over their own mouths because they can't stop talking. They say there's no other way to stop talking. One of them even said, "I want to stop talking because my mouth is tired, but I can't." I always made them take the tape off but it's hard not to see it as a good, if temporary, solution.
Two years ago: Lou Dobbs
Three years ago: Butterflies, Warren, and Suzy