Ejaculation during sex is not guaranteed for every woman. It's thought that only about 69% of women can do it. Some women do it and don't even know, while others can ejaculate on demand. In any case, just trying to make it happen is a lot of fun.
Whether you're considering circumcision for your newborn son or thinking about circumcision for yourself as an adult, the final decision should be made according to your personal views and the medical advice of your doctor.