Just make sure the dog doesn't try to pull out before the knot goes down.  Have the owner/trainer ready to prevent that.  I took the German Shepard's knot.  I'd do it again but the owner moved away.  I have never felt so full.

You're not the only one with this fantasy. I hope you get it. And I hope you will post again to let us know how it goes!

I am also looking for a knot stretching my ass to capacity.

I have felt the knot twice.  A fuck bud had a friend who raised dogs for fighting (a nasty concept...but basic part of story).  He also was training some to fuck humans.   First time I went there I just watched the proceedings as a guy got his ass hammered.   A few weeks later I was invited back to "help out" with a "demo" (He had some customers in to consider buying one).    

Anyhow, I had barely stripped and gotten into position when they brought the dog in....and beautiful boxer.   That dog was there to fuck and I was hardly prepared.  But he mounted me and found my hole like a master.   Once he found the mark, he fucked like the animal he was.   He blew a load kind of quickly and swelled up his knot to seal the dog cum in my ass.   The knot was intense and he was bored.   He kept trying to pull off---and seemed to be intent on ripping my asshole out with each movement.   Eventually he settled down and we stayed tied for almost 20 minutes.   Once his knot was less intensive, he went back to fucking and gave me a second load of puppy seed.

A month or two later I got invited back.  Another demo, but I was more prepared.   The dog this time was not as well trained.   It took him some time to find my hole and even longer time to find a way to get his dog prick inside.   Once he got hooked up in my ass, he gave me a nice fuck.....compared to the boxer.   Actually, for whatever reason (maybe my own preparation) it was a pretty great experience.   He started to knot once he flooded my ass with his seed, but never really fully tied into me like the first one.

Not sure it is something I need more of, but am glad I experienced that in my past.   Would still like to do a donkey show sometime.

wow..thats a flash back nightmare...I was very young when a neighbor guys dog took me down..he had his paws wrapped around my waist..I was so scared i just froze like a deer in the headlights...when it was all done I ran home crying covered in dog juice

Sounds like a great experience.  I recently found a Daddy that allows me to suck his Shepard and I'm looking forward to Daddy taking it to the next level to knot me.

It is very enjoyable and knot is just incredible. Be sure and relax and have some one your comfortable with. Don't rush it

Find somebody that is well versed in it as a real training dog a well trained one . I'm very lucky to have been in the right place with the right man (actually it was a couple male female) never very into it they were very into it and sharing the experience with others

And that's what you did as a hobby was race trained or was to raise completely trained male intact dogs.