Try fucking some good woman's mouth

Try this. When you ar masturbating, don't make a race of it. Take your time and let the arrival of your orgasm ebb and flow. The longer you take, the longer it builds. When you at last get "there" your orgasm will tend to be more powerful, deeper, and you should experience a greater amount of ejaculate. See if this helps and post back.

Sperm amount varies from man to man, but you should consult a doctor if you have doubts in your health. Also, more frequently you masturbate, less sperm you get each time.