hi.. i have understood your concerns.. actually night fall is a normal phenomenon when u are not sexually active either by masturbation or sexual intercourse.. our body has sexual glans which produce semen regularly, but they have limited capacity for the storage..so u are not masturbating and not removing the semen by any means then your sexual glands have become full of semen and now whatever extra semen is produced daily is coming out at night when your penis becomes hard..or it may come out whenever u have excitement and erection even during the day time,..or during passing urine or stool when your abdominal pressure increases which presses your glands.. so there is nothing to worry, u feel weakness because u are thinking that your semen is very precious thing and it is getting wasted without any reason..but my friend it is produced for wastage only unless u have become sexually active and u are married..when u plan a baby after marriage then only it is important, till that u have to just waste it..otherwise it will come out at night regularly.. i ll suggest u to go for masturbation regularly with a frequency of 2 to 3 times in a week..when u masturbate your problem of night fall will stop on its own... i hope u ll find this advice helpful... best luck..