system
Given the following post, respond as if you're commenting on Reddit:
human
ElI5: Why do you ‘double over’ or hunch over when you have a stomach ache or have eaten too much?

Why do you hunch over when you have a stomach ache or have eaten too much? And why does groaning kind of make your stomach feel better when it’s aching? Could you be hunching to take pressure off of it or something..? But then wouldn’t groaning put that pressure back on??
gpt
Your body's natural response to pain is to contract muscles. On the same token, your body also compels you to apply pressure to injured areas because of survival instincts telling you to reduce bleeding.

It turns out that entering the fetal position 1) allows you to contract your muscles without needing to stretch them and 2) applies pressure to painful areas by contracting your muscles.

Your body works in a strange way where your nerves are very easy to saturate with a signal, so your best bet when in pain is to apply pressure because the pressure can essentially help to reduce the pain that you feel. The fetal position is just a natural response to apply as much pressure as possible to your groin/stomach area.