I had an experience once, but it was not the best...
I moved in with a kinky boyfriend right out of highschool. He wasn't a Master, in the true sense; he was simply a sadist. He had a party one night, and invited four of his guy friends over, and then asked me to blow off his Rottie.
I refused. Animals are one of my hard limits; I don't do them. And he knew it. He got mad at me for refusing, and dragged me out ot his backyard. It was summer, and he had a lot of trees there, so nobody saw but him and his friends...anyway, he tied me spreadeagle between two trees and whipped me. I was gagged, i couldn't use the safeword we arranged, and i think he was too drunk to see my hand signal. He cut me down from the tree after almost an hour, during which time all his friends had a go with the whip at me. Then he cut me down and had all his friends, plus himself, piss on me as i lay in the dirt. Then he hogtied me and left me there all night with the mosquitos. The next morning, a bee drifted by and stung me.
I'm allergic to bees; I go into anaphylactic shock when they sting me. I have a MedicAlert bracelet I wear during the summer months so if i do get stung, people know what to do.
I went into shock, and passed out. When i woke up, I was in the hospital. Don's little brother had come by to let the Rottie out and saw me there, and called the ambulance to take me to the hospital. If he hadn't I would have died.
If you do chose to indulge in any fantasy involving animals, please make sure all parties are willing.