Jackknife

The action of pulling your pants down while driving, squatting above the seat, reaching your hand underneath your bottom, defecating into your hand, and then using the feces to smear your windshield. Done ritualistically for courting purposes.

The man decided to jackknife while driving on highway 99, in an attempt to enamor his lady friend.

There are people who jackknife to relieve stress during bumper-to-bumper traffic.