True benefits occures when you don't get aroused at all!

This is what I understood from Ayurvedic views on semen retention. Feel free to correct me or give your views.

Semen (or sexual power) exists in all cells of the body... Nourishing them in it's fullest extent.

When one gets aroused, energy starts getting concentrated in testicles converting into sperm and other seminal fluids. If one doesn't ejaculate (in case of edging or sever sexual thoughts) .. a small part of that gross semen might get reabsorbed but majority leaves the body in one way or another.

So it is safe to not get aroused at all... I.e. true celibacy.

It takes 3-4 months of celibacy for the body to stop producing excess semen ... After which various physical benefits starts surfacing.

When one mediates and transmutes that cellular level energy... It becomes ojas and gives spiritual benefits.