Volume of the ejaculate (cum) should be measured after 5 days of sexual abstinence. Under those conditions, the volume of ejaculate should be within the range of 2-5 ml. If your ejaculate is within this range you don’t need to physically increase it. Further, the amount of ejaculate is only one of the parameters used for evaluating the quality of a man's sperm. You can request a spermogram to examine the other aspects of sperm quality which include: liquefaction time, spermatozoid count, vitality, mobility, morphology, etc.