'Nightfall' or nocturnal emission is normal phenomena occurring from adolescent age. Nothing is abnormal about it. It has got no relation with the fluids you consume. The secretion of prostrate gland, seminal vesicles and Cowper's gland and sperms from testes form semen. Nightfall is one of three natural ways of discharging semen from body after sexual arousal, other being sexual intercourse and masturbation. Semen production takes place continuously day and night from adolescence to old age group.