Non zoo: Participating in a “Stutenmarkt” (mare market) event. These are organised every couple of weeks in a gay bar or gay club in Germany (Cologne, Stuttgart, Mannheim or Berlin) and some times in Amsterdam. You can participate either as a (human) stallion or mare, whatever your choice is, you stick to it for that event. I would particate as a mare. As a mare you show up a little earlier, to be prepared (informed, stripped and blind folded with a sack over the head). You can express your goes and no goes and then offered to all the stallions, who are all waiting in a room. You don‘t get to see who picks you and uses you in front all of all the guests. Once a stallion is done with you, the next can pock you… and it goes on the whole evening, unless you (as a mare) can’t take any more and wish to be taken back to the “stable” and leave.
Zoo: Being fucked by a dog (and watched, ideally by a group)