I think prolonged semen ritention is not good at all. After i did 6 months of sement retention in 2018 i started having problem urinating, which i still have. I would not suggest to do semen retention for long periods. Once in a while u should masturbate (without porn) or have sex. That's my take on semen retention.
Well I have done semen retention in various bouts with the intention of letting my body getting used to releasing less (been going on for about 3 years now). In the beginning it would just come out by itself almost every night, but I never really paid much attention to any changes "down there". All I know is, now I don't leak everyday and I have more energy. Now, I am doing it again for at least 40 days but for a different reason.
I had to learn some tantra type exercises to channel the energy. I do simple breathing and stretching exercises that make this not an issue and helps channel the engergy to your higher self so you use it instead in your meditation, creativity, physical exercise, and over all healthy life..
It's not an energy issue, it's an issue of too much sperm in your balls that become almost silicon like...