Enlarged right testicle and veins after masturbation (2times/day, noticed enlargement <1hr). Even that testicle is slightly hanging down and painful.21y?

Testicle problem. There are several possible causes to your problem . A testicular torsion which should be seen by a doctor quickly or varicocele .. Please see a doctor soon.
Varicocele. You may have a varicocele; please make an appointment with a urologist to examine you and see if that is the case.