Why when you are nervous or shock. the p***s will hide in the t******e or smaller

Question

Why when you are nervous or shock. the p***s will hide in the t******e or smaller

Answer 1

Do you mean, why do your balls draw up against your belly?  If that's the question, then it's means of self-protection.

Answer 2

When I'm nervous or shocked, I've had other things to focus my attention on than what the little man is busy doing.  But yeah, it's probably a protection reflex.