The act of fulfilling one's ambitions, desires, etc., through one's own efforts best defines

The answer is self fulfillment

Explanation: self fulfillment is something you feel when you put your best self into a task, job or just plain out life we all feel self fulfillment but only when this happens.

when you rub, you also apply pressure, that pressure can urge the poop to come out. i think that when your rubbing, you also might be slightly breaking it up and that can further fill the stomach.  

answer; monaxial;