Only way as you say it, yes. Come to know and become friends with someone who might be willing to let you try.
I personally see no biggies in someone giving a good friend a chance to try given all parties agree.
But just meeting someone for that... is both a nasty thing and dangerous.
I'd keep away from personals section and be active in the forum for months/years. Once peplo know your thoughts and are familiar, you may or may not find someone you click with.
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On a different level... A post like this is a big red flag for me.
Shows you are only looking for a sex experience rather that finding a like minded person, getting to know animals, learning how to live with one and looking for a way to one day keep one.
Looks quite like a one time experience. I would not answer you as it is now.