only immature sperm are stored in the testicle, as they develop they work their way to the prostate for use. The prostate mixes them with seminal fluid and that is what makes up the volume.
What your asking is if a castrate male can have sex, yes, some can, but most loose the desire as testosterone is made in the testicles also, which converts to DHT and that is what fuels your sexuality. Most castrate males who don’t have prostate cancer go on testosterone replacement therapy to keep health up as there are a multitude of side effects to androgen deprivation, depression and bone strength loss are the primary ones. The adrenals also make a small amount of T, and that is sometimes enough to get by, but most of the time it isn’t. Obviously, castrate males can not make sperm and therefore are sterile, but they do have fluid as that is made in another gland.
Yes, im a castrate male on TRT, so I know these issues 1st hand. All desire and drive is lost if i stop hormone replacement therapy, but i function still, just cant reach oragasam very well, and it dosnt seem important. When im on TRT i am normal.