If you have history of excessive masturbation,that might be the cause. Do you experience semen leakages?
is there a way to relax those muscles when they tighten up, when im trying to hold them in?
Hi,
You mean to say that when you try to hold motion, your scrotum moves up and penis gets tightened?, if so, it is natural as in the process you are tightening the PC muscle, which has connection to both ano-rectal muscle and pubic muscles that control other pelvic organs. Google for ' PC muscle ' for more info.
Solace