John Legend sings about 4 hour erections in latest Carpool Karaoke

John Legend and Alicia Keys joined James Corden in his latest Carpool Karaoke episode, and he challenged Alicia and John to an impromptu jam mesh inspired by gross topics.

Keys had to sing about the woes of natural deodorant, but the real showstopper was Legend's ode to erections that last for more than 4 hours.

Check out the video above.