This exercise is pretty much exactly what it sounds like. You begin with a body weight squat, with hands held on head. Upon returning to the starting position, meet one knee with the opposite elbow in front of your body. On the next rep, meet the opposite knee with the opposite elbow.
Focus here on rotating horizontally with your elbows and bringing your knees up as high as you can get them. Your knee and elbow don’t have to actually touch, but bring them as close together as you can.
As always, on the squat, push your hips back and push through your heels. Try to get low to the ground to help increase the range of motion through the hips.