Originally Posted by Fantom
Sounds like a pretty normal function to me. The cremasteric reflex (which you can test by running a fingertip down the inside of your thigh), does the same thing. Not sure how the kegels are involved, but probably related to muscle contractions in the entire perianal area involving the same group or set that lifts the testes.

“cremaster” is the name of the muscle, which usually acts involuntarily… pulls the scrotum/balls up during cold temperature and height of sexual arousal. Some guys (as already noted) have the unusual ability to contract this muscle voluntarily.