Sorry to ruin your fantasies but the average woman can't take the length of a large dog plus the knot. It's more likely only a small percentage can.
I agree with you there when you say that only a small percentage of women can take the really large dog cocks deep enough to get those really large knots inside them.
Still, I've been surprised to see how long of a dog cock a few women have accommodated, knot fully inside. The brindle cross breeds or mastiffs have seemed to be the ones that have the longest dicks in the homemade vids, along with a white shepherd. See "Morning Knot" for a woman that takes a mastiff or mastiff cross in deep. There's a couple from back in the Beastforum days that had a brindle that looked like a lab cross, that had a long wang too, and she'd take it to the hilt and tie for minutes at a time.
In the pro porn, that giant schnauzer had the longest I've seen in a penetration.
You're also not going to see a person tie with a dog vaginally. I would say it's possible anally but I think you would probably tear if the dog pulled hard.
I lost my virginity to a german shepherd. We didn't even come close to being tied. I think that would be my best chance to tie. Human pussy was not designed to be tied. It would be nice if we could tie though
I guess it might depend on the deifinition of "tie" that someone uses. Truly stuck quite hard to be able to turn the tie easily? That is more rare with the human vagina, yes. I've still seen a couple of ties, on homemade clips, that were stuck enough to pull a woman over on her side.
Ties lasting 6 mins + still do happen, even with them turning the tie. It's a bit more rare, but can be seen in one of the Barney & Frankie clips. Barney was a bull mastiff. In one vid he stays in Frankie for 6 + mins.
There's a lot of variables that factor in as to how long a woman can do a soft tie with a dog. Soft, as in he isn't truly stuck, but the fit is snug enough that if he doesn't pull too hard, or turns around slowly, his cock will stay in her for several minutes.
A wider knot will help him stay in, but if he stays on her back, if little to no air is in her vagina, and the angle he tugs out all make a difference. If a dog pulls up and forward, the knot won't come out as easily compared to when they pull straight out.
Danes on vids:
The famous Hector from 20 years ago pretty much never knotted a woman. His cock was really long, as people have mentioned on this thread. One woman came close. I saw a pick of a spotted white dane with a super long cock too. The woman had red lingerie on. Some of you might have seen it.
A vid from the early 2000's had a tall and thicker woman wearing a white T-shirt taking her spotted white dane pretty easily. She was standing up and bent over. His cock wasn't huge, and they didn't tie at all.
Knotty did take her dane in more than one vid. In one you can hear her queefing a lot as his big knot moved in her a lot with a good bit of air too. He had a wide not with a short shaft, like the pic on the 2nd page of this thread. So, he was not too long for her.
Mastiffs: The woman called Andrea that was one of the women with Stuppi's ponies (blonde, maybe greyish in some vids), took a large mastiff. She took his knot too. I think they tied for a bit, but I can't remember enough of that post.
Morning knot- I'm pretty sure that was a brindle mastiff, but his hair is a little on the long side. Maybe it was winter, or.... I don't know mastiffs well, and some might have longer hair. She tied with him for a minute or more each mount, I think. I only have one clip of that right now, but I think there were 3 bouts of fucking and knotting, one per short clip.
There's probably other mastiff on women vids that I don't know about.