When you're so overweight various body parts applaud you upon running...or even just walking faster than usual.
Most commonly referring to thighs and breasts, but only when breasts clap against your stomach no each other (that's cheating).
Can be prevented by wearing sports bras or support pants, but inevitable when dashing around in pijamas because the food delivery guy has been knocking on the door for three minutes but your keys are nowhere in sight.
My boyfriend heard my body clap for the first time this morning!