Thanks for query,
Just remember that excess is always poision.
2-3 times a week is a common practice in your age group.
When you do it excessively due to rubbing your urethra
gets irritated & you got pain.
Sexual act has four stages arousal erection ejeculation & lag period.The lag period may extend from 2 hours to 72 hours.If you do masturbation again in this period you may not get erection.