Yes, the number of ejaculations does speed up the process. At the American average of intercourse 2 times per week, an average of 16 ejaculations or 2 months is required for most men to achieve sterility. More frequent ejaculation than 2 times per week can reduce the time to achieve sterility. It is noted, however, that most men are sterile after 3-4 months even with no ejaculation.