Following puberty, adolescent boys undergo hormonal changes with enlargement of the penis and a feeling of sexual desire. As a result, they tend to have sensual dreams with sexual content, and this can cause involuntary ejaculation during sleep.

Although, some men can be awakened by nightfall, others may sleep without realizing it and notice it only the next morning on their underclothes or bed sheets.

Contrary to existing myths, nightfall is not a sign of disease and it will not reduce the immunity or make a person weak. Nightfall will not shrink the male organ (penis) nor will it reduce the sperm count or result in infertility. Nightfall releases the stored semen and fresh semen will be formed in its place.