There must be alot of people who don't ejaculate for over 3 months straight, so don't worry about you being the pioneer in this field. The sperm ur testes produce only survive for a short time in your body anyway so there will be no build up as ur testicles re-absorb ur sperm and produces new sperm cells. This is happening as we speak (or type). So, this vow (or dare) that you will embark upon will not harm you. (If it's a dare, no chance you'll make it through the 3 months, lmao)
I'm not an expert on this but I would think that any excess semen would be discharged during your sleep in the form of a wet dream.
does anyone have advise on this???