What is the definition of tieing?

[throwaway13337]

I am new and was wondering what tieing really is. Is it that the knot gets so big that it gets physically stuck or is it that it gets so big that it hurts too much to push it out?
I don't know the details on how the female anatomy works but what stops women from pushing the knot out when they can push out a baby?

 

[pes]

Technically tying/knotting is only possible for female canines.
The human vagina does not have the musculature that allows the knot to be stuck in the vagina.
Some people can achieve a tie, but it is rare and in fact in the vast majority of porn, you can see the dog slip out of the woman with full knot without any effort.
All the porn where a dog makes 10 attempts to mount a woman and fails is another symptom of the lack of the ring muscle that holds the knot in a female dog.
Most people do not understand that providing a grip on the knot is essential for a successful mount and orgasm and for the dog to keep an erection and this is something the human vagina can not do in 99% of cases. So you should put your hand down there and hold the knot in your fist.
Not holding the knot is a signal for the male dog, that sex has finished.

The knot is the bulb at the base of the penis.
In a lot of photos you can see that the back side of the knot is very red and full of blood vessels and nerve endings.
The knot provides a lot of stimulation to the dog just as the tip does.
The shaft on the other end should not be touched and that is also well visible from the lack of nerve endings in that region.

 

[HammerTongs]

I'll add a bit of a note here - if the woman is small enough, and the dog is endowed enough, the knot can be physically wider than the vaginal canal, and can "tie", but this is generally uncomfortable the first several times for the female, requires patience, and is the only way a woman could possibly be dragged - essentially, if the knot is larger than her fist, and she cannot physically fist herself, then this is a likely outcome. At the very least it will be painful to withdraw the knot before it's subsided.

By small, I mean Inke and her mastiff, and I'm not entirely sure there's any evidence she actually took his knot - the shaft itself was the size of her forearm, so the limitation on being able to tie, is being able to accommodate the length which comes with girth. There aren't a whole lot of long, skinny canine penises any more than there are short thick ones, they tend towards the same aspect ratio, so... your mileage may vary, but not by much.