system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5 - What is the weird sensation you feel when you clean your bellybutton?

Okay, I hope I explain this well. Every time I clean my bellybutton, I get a really weird, almost painful sensation deep inside my body (not immediately below the below button) but a little lower and deeper inside. What causes that to happen?
gpt
The inside of the belly button like around the abdominal cavity is exquisitely sensitive and its sensory nerve fibers relay input back to the spinal cord at the same level as the nerves that relay sensation from your bladder and urethra. So it feels kinda like pain from your urethra but it’s not coming from there, that might explain why it feels deeper. Cuz it’s like coming from not as far down and you mind ain’t used to it, or something.