what sort of side effects
Hi,
It is not good to masturbate at that age....tell him wait till he grows up, masturbation has side effects if done excessively...I am suffering from them now.
Regards,
FWK
well he sounds a bit young to be masturbating and that age is certainly outside of the average male puberty range by about 4 years. But if he understands what he is doing you maybe should tell your parents and make them give him a "talk"