Answer: After a vasectomy both the ejaculatre and pre-ejaculate will continue to have residual sperm for approximately 3 months, though in some men is even longer. That largely is why your urologist has you schedule the follow-up appointment.
Answer: Sperm in ejaculate can likely stay alive for a short time as it passes from the mouth, through the esopagus, into the stomach. But there, stomach acids would treat sperm as anything else ingested: acids would begin breaking down the ejaculate into whatever could be used in the body as energy. As the fluid of ejaculate passes into the small and large intestine, it would be treated as any other fluid ingested; the intestines help maintain fluid balance within the body. Any "nutrient" value would be passed to the cells, just as any other nutrient. The by-products of sperm and the ejaculate fluids would then be excreted as any other bodily waste, either through the urine or mixed with stool to make a bowel movement.
One consideration with ejaculation into the mouth is that, like any other item that touches the teeth and gums, oral hygiene would be important. Rinse with water, and brush the teeth, gums, and tongue as you would do normally. A good mouthwash will help remove "sex odor" as well as washing the face and neck.
Answer: Well twice a day would lower the concentration and it does take the body time to reproduce more sperm but, I doubt it would lower the count enough to make a difference. My husband and I had sex 6 times a day for the first six months of marriage and I still got pregnant.
Answer: Stimulate the penis--usually through stroking by hand, vagina or anus--until the man reaches orgasm. The ejaculation will happen naturally.
Stimulate the penis until orgasm. Ejaculation will follow quite naturally.