take turns seeing if someone can do a sit up while someone covers their face with a towel and holds the towel to the ground, then someone squats over their face and spreads their ass cheeks, then as the person is trying really hard to do the sit-up, slip the towel off, and watch as their face gets buried between the fat sweaty ass cheeks.
"bet you can't do an olympic sit-up"
"WTF!! OMG!! WHY would you!!!?!?!?"
"that was a very shitty sit-up"
olympic sit-up sit up shit ass