hello there. night fall is normal.if you don't masturbate and take it out. think of it like this, what happens if you keep pouring water into a bucket which is already full? it will overflow right. just like that, sperm production is a continuous process, it doesn't stop. so when there is excess, the old ones come out in the form of night falls. so its actually good to masturbate 2-3 times a week. just drink lots of water and eat healthy. there is absolutely nothing to worry about. regards