Hello and Welcome to ‘Ask A Doctor’ service. I have reviewed your query and here is my advice.

Night fall or wet dream is a natural process and almost every fertile male has experienced it in his life some men experience it on regular basis while other once in a while.You need to understand that night fall is body's natural way to get rid of old sperms to make room for new sperms as the process of sperm formation is ever going in males
Some men have frequent ejaculations either by masturbation or by sexua intercourse and they will experince night fall less aince there sperms are already moving out of body while other males who do not ejaculate on regular basis will auffer night fall more. Night fall frequency has nothing to do with the feetility of a male.

Thanks