This is good advice. There's more than an incidental correlation. Don't go thinking most of them will be, but in my experience, 50% to 60% of the women that collect fantasy dildos like zoo fantasies as well, and most of those that like the fantasies say that they would probably want to get mounted if they felt safe and the dog are pony were to get aroused and want to breed.
I spent years on the old Bad Dragon forums before it got deleted. I would build up friendships geeking out over big toys there, then after a certain level of comfort I would ask them about zoo sex fantasies or erotic stories. Don't just throw out, "would you like to get fucked by a dog". That's too blunt and lacks nuance. With real people there is nuance.
Someone else mentioned Fetlife and munches. That's another pool where the interest in zoo sex will be higher than in the general population at large. I have gone to just a couple of munches, but never enough to build that much trust. On the other hand, I did go to one particular kink party monthly. I got to know the hosts well enough and after a couple of years asked them if they knew of anyone into zoo sex fantasies. They said no, but seemed to like that I shared something so private.
Then, I was in the polyamory community for years. I'm still on the fringes of it, sort of. At one poly Halloween party I admitted that I liked incest stories and aslo zoo sex stories of women getting bred. There were only 2 women in that conversation. Neither of them I was attracted to. Both admitted to liking zoo fantasies, and one started gushing about tentacle porn (not my thing). I think someone asked the people on the couch what their naughty kinks were, and I threw mines out there, and was glad to see it wasn't shot down. I had a feeling those few people would not be judgemental. I think others at that party would have been. Try to sort the people out that are strict rule followers and avoid those that correct people a lot.
I have been looking for this since I'm an adult. I probably told the most friends with benefits women this, back in my 20's. These women that were having casual sex with me, and were the type to want threesomes, were usually at least somewhat curious about getting mounted. 2 of them wanted it, but I wasn't willing to risk it with them in case they would get mad that I didn't want a long term loving relationship with them after. 2 other FWB's were the type to like BDSM restraint fantasies, and said that after they'd be willing to be mounted if they got tied up and blindfolded. Both of those last 2 were more conservative/lived in more evangelical or Baptist areas.
Overall Opinion
It's wise to peel the onion slowly. Be sure you can have conversations with them about fantasies or naughty things that are maybe kinky, but more tame. Then, if you like stories of consensual incest, that seems to be a baby step to seeing how they will react. For me, I'm more comfortable admitting that. I'm sure there's other mid-way fantasies that reveal how they react to admitting edgy kinks. Maybe it's gang bangs, casual sex without condoms (are they a rule or norm follower? ) maybe it's fantasy dildos...... Maybe it's consensual non-consent fantasies, or maybe it's a threesome with a stranger invited, and she is blindfolded.
There's going to be some zoo women that are not into BDSM or other edgy kinks. The only advice I can give with them, is look for the type that genuinely loves animals. They might have studied biology in college. Try your best to see their opinion about social norms and strict rule following before mentioning anything zoo.
For example, I'm friends with a woman that works in the field of biology right now. She owns a male dog and is against neutering. I've been very tempted, but I haven't taken the risk to mention zoo sexual stuff. I'd have to figure out a way that isn't blunt or overboard, but maybe is more about zoophilia and zoo relationships, rather than from a kink or fetish angle. She's also not monogamous.... so.... yeah. She does think outside of the box.
Meeting from Zoo forums
The best advice is as those people said, just build friendships here. If you engage on more of the non sex-focused threads, you might learn how to more accurately tell the sex of the person posting. They might reveal it in a few posts out of hundreds, but also appear real in a number of ways.
Don't be naive and move fast. I've mentioned it on other threads, but I was setup by an undercover the hooked me on Beast Forum. Thankfully I was much wiser in person than I had been on the tech savvy front. I never propositioned her. Her questions became more reaching, and I sniffed out the rat. I was tempted to become a smart ass, but I ended the visit smoothly and safely went home.
I had also met with a man/woman couple off of BF. They were indeed real. She was reluctant to get mounted that day, but she called me a few weeks later and was ecstatic that she had experienced it. Weeks later she was more comfortable and ready, and a different owner had an experienced stud. She thanked me for the visit again. Sometimes real couples only post to the personal ads section. They are more used to the swinger / hotwifing world, and they don't engage in the long conversations elsewhere on forums. They are used to going in and posting an ad, then meeting up, when it comes to adult sites. Even though I think most of these couples are real, still be careful and try to be wise, if anyone reading this is considering meeting with a couple. Now and then real couples are owners and are looking for women that will go have an experience with them, especially a first time experience.
Good luck!
Edit to add:
I mentioned my Bad Dragon toy collection on an Okcupid profile once. It didn't help me, but I also didn't get into any trouble or get my profile deleted. That was probably 5+ years ago. Things might be different now. It's probably worth mentioning fantasy dildo play on an r4r ad on reddit, but again, don't go asking for zoo sex interest soon. Supposedly, before Craigslist personals was done away with, posting an ad about your horse dildo might get you some unwanted replies from people that want you to do time, if you actually had a dog or pony available too.
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