Renee
Citizen of Zooville
The cervix is sensitive, yes, and more so at some times of the month than at others. What usually happens though, is the tip of the long or large dog penis will go up beside the cervix and past it by 2 or 3 inches. So, the vagina is stretching in deeper. There is a hard limit, eventually. It's not like some people think and always just left up to how high arousal is.
In fact, it's not that super high arousal makes the vagina "tent" even more, which it might, slightly. An overlooked side effect of very high arousal is about a 120% increase in their pain threshold.
Some "poking too deep" can still happen even with high arousal, but that's likely not what most of the women describe here. It's mostly going to be from the girth of the knot. As others have pointed out, it swells really quick! In the ideal situation, the dog's penis enters the vagina when nearly still at it's smallest size, or when semi erect and maybe 40% enlarged. Within about 3 to 5 thrusts the knot is full width.
They often plunge in rapidly too. Some medium and larger dogs with experience with a woman will move their hips a little slower till they feel the tip of their penis start to enter. Very few push all the way in a slow at first entry. It's more that they plunge it in. If it's no more than half erect on the first thrust, that's rarely too deep. In 3 to 5 seconds it will be full size though.
So, it's typically the width, and some women don't feel much discomfort from a large girth. It really varies a lot from woman to woman, and if she hasn't been taking larger penetrations lately, a larger dog cock will likely cause more discomfort than it would had she been mating with him at least a couple of times a week.
Women that use really large dildos tend to see a loss of stretching progress after about 2 weeks without penetration from anything above average in size. Some of them, not all of them.
by submitting to his raw power
