You got it wrong. Please read this:
Oral sex it more or less about masturbating a male dog with the added benefit that in the end you do the masturbation with your mouth. So lets begin with how to masturbate a dog. Castration/neutering: The purpose of castration is the removal of sexual behavior. "Another benefit of castration is...
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When you are having sex with an animal, you should really understand the anatomy first.
Porn does not teach you anatomy. If anything it mostly shows you how not to do things right.
The knot does not come out on its own. In normal mating with a female dog, the penis goes in flaccid and the sheath is pushed back by the tight vulva. When the knot inflates, the sheath is held back by it and it stays exposed.
This might not happen with a human vagina which has a different shape.
Humans can not knot in 99% of time.
I'm sure this has been asked numerous times but my gf and I are new to this, well she is actually. I've been watching beast for years and recently introduced her to it and luckily she's accepted it and agreed to try. Our pug licks her like crazy and our Pyrenees not quite as much, but we cant...
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So you are going to have to use your hands.