Minutes after repeating his familiar warning that sometimes he does not know when to stop saying all that he means, Vice President Joseph R. Biden Jr. let out quite a quip at Harvard’s Institute of Politics Thursday night.

When a questioner identified himself as the vice president of the Harvard student body, Biden chimed in, “isn’t it a bitch, I mean … that vice president thing?”

Knowing what had just come out of his own mouth, Biden quickly added ”I’m joking. I’m joking. I’m joking. The best decision I ever made.

“That was a joke. That was a joke,” he continued.