Dad taught me as well, but already brought the lube and had a small bottle of poppers to help relax us both. Hit me again. Loved sucking that old man. Showed me the joys of dad and son bonding
Maybe the full-length video shows where the father explains the parts of the penis(shaft, base, glans) and mentions that some penises will be circumcised like his and the son's, that some erections will be curved, sometimes one testicle hangs lower than the other, masturbation techniques and there's so much more).
No, the testicales are not where semen is stored, but are only for the purpose of producing sperm cells. This doctor better read up on the male anatomy again!