I've read that they can mate up to five times per day. However their sperm production is reduced by 1/2 at the fourth mating. Also daily mating will reduce overall sperm production to what their body produces daily, with no time for a cached supply.
Unless it was being manually stimulated, it probably couldn't do it ON a human, but there are for some reason people who have sex with dogs for reasons including they can't get pregnant...which would...
A male human can theoretically go his entire life without ejaculating. But who'd wanna live that life? Actually a male does need to ejaculate periodically throughout his life, especially early on....
Depending on how much celery, cacao, and other arousing and sexually stimulating aphrodisiacs, men can ejaculate 6 or more times in a day. Other factors include how attractive his partner is and how...