The best exercise is the one where you burn calories. These two skinny teens decided that for them in order to keep their lean bodies slim, they need to have sex. What better way to do that than with high-intensity fucking. Since the instructor was there, they threw him in the threesome. Started off with kissing, and ended up with a cum swap, but in the middle, they burned fat hard. Doggystyle and pussy eating was 300 calories easy. They are bound to come back for more.