Because of quick and efficient , young adults can rapidly adjust to any stress and bounce back quickly after running a marathon or missing sleep.

Homeostasis

Explanation:

Homeostasis is the ability to maintain a fairly constant internal environment in response to environmental changes. Homeostasis is the automatic maintenance of a steady state or state of balance within the bodies of all organisms. Living things possess inherited or naturally built-in, feedback systems that help them to maintain a stable internal environment, even when the external environment changes. The central nervous system (CNS) plays a significant role in the body's stress-related mechanisms, and the CNS works closely with the endocrine system to regulate these mechanisms.

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.