Masturbation

i know that masturbation is frowned upon. but how much of a sin is it? and, i can’t believe that teenage yeshiva bochurs don’t do it, so what’s their rationale? if it were truly a sin, wouldn’t men have to get married by 12? this is a serious question, so please don’t dismiss it as frivoulous.

Shalom U'verachah, Wasteful ejaculation is considered by many to be a Torah prohibition and even masturbating without ejaculation is prohibited. This is indeed a struggle for many young (and not so young) men and the religious man tries to overcome his urges and serve Hashem. Kol Tuv