Hi, I know that there are different sizes of horses. I guess I'm wondering exactly how much horse cock most women can take in inches of penetration. I guess the simplest answer to this question should be not enough. I'm wondering, is it possible to train women to relax their cervix sufficiently to allow for full penetration? That would give substantially more distance of travel.......not to mention, a place for all that wonderful semen to collect.
Lose any idea that "any woman" can "relax their cervix", for starters. That simply doesn't happen, though you'll hear wank-hounds who will swear up and down that it does. And yeah, there are a couple of mondo-freaks - they just go to prove the general rule.
Now, having said that, how deep is this particular woman you're talking about? What's the size of the stallion you're thinking of trying her on? Mini? Pony? Cob? QH? TB? Warmblood? Heavy? And within that category, how is the individual stallion of that breed/type endowed? Is he a mini with a not *SCARY*, but definitely bigger than a typical man's tackle? Or are you gonna get ambitious and see if she can take a drafter stud, which are, BTW, where we get the expression, "hung like a horse"... I mean... swinging meat close to the size of one of my legs on a full ton or more stallion that's likely two heads taller than you at his shoulder, in full "I wanna make you pregnant!" breeding mode... Nah, I'd hafta say that probably isn't a survivable scenario by any randomly chosen human female - Or male, for that matter... PERHAPS, with MUCH effort, pain, and training time, someone deranged could attempt it, under carefully controlled conditions, but I wouldn't give odds on their chances of not doing some variant of a re-enactment of the Mr. Hands incident in the process.
In fewer words, "Too many variables to say much more than "how deep is she comfy taking how big a horse?". It also tells those of us who have some decades of experience with actual horses, both with and without sex being involved beyond the inevitable "I'd hit that", that you're nowhere NEAR the knowledge level to make (or supervise making) the attempt. Doing so will likely get you/the "catcher"/assistants/the horse, or some combination of any or all of the above badly damaged, perhaps even dead, and not necessarily because his pecker rips said catcher open.