As usual left and right counts as one rep!
Lie down on your backs with your feet facing your partner. Hands at your sides pushing your palms into the floor. Connect the soles of your feet, it’s easier when you push into your partners feet.
Then switch switch switch till you’ve completed the reps!
You can see my brothers hips are lower to the ground than mine and that’s the modified version. The higher you lift your hips the harder it will be!