When a man uses his hand to move his penis in the H-Pattern of a manual or "Stick" shifter like he is shifting gears on a car. Often, the man will also use his girlfriend's boobs or vagaina as a steering wheel or clutch pedal.
Person 1: Man, I did the dick shift really hard last night, and her boobs were the perfect steering wheel shape
Person 2: Did you hit the perfect downshift?
Person 1: Yup, and I finished soon after. It was awesome! Will do again, 10/10!
The sex position in which the male is laying on his back and the female sits on his stomach. Her feet are on his feet working them like petals while simultaneously working his dick like a manual shifter. The male has the option to then use her breasts as a steering wheel.
Hoe: "I'm thinking we ride the dick shift tonight."
Guy: "sounds great! Let's go through a hilly landscape? There's a lot more shifting and turning involved."
Hoe: "I get tired of shifting and you gonna stretch out my boobs!"
Guy: "you wanna fight bitch!"