>around ten years old
>at friend's house overnight
>we were tuckered out from video games, and laying on couches
>time to sleep, tired, but his dog came to lay with me
>his beagle liked me a lot, because I was always nice to her
>friend and his family were all assholes to the dog
>she was on same couch as me, we started cuddling
>pretty sure friend was asleep, his family were all asleep hours before
>I know next to nothing about sex, but feel drawn to beagle's cookie
>start rubbing it, she is receptive
>decide to try fingering her pussy
>again, I know next to nothing about sex, so I tried to go in dry
>she tolerates my awkward attempt, up til the first knuckle - then lets out a "Yip!" and jumps off the couch
>friend was still awake, asked what happened
>panicked, I bullshit him that I must have put too much weight on her leg or similar
>he buys the BS, she goes to other room to lay down, we all went to sleep
>never tried with her again, that friend and I stopped hanging out, because he was asshole
>still attracted to beagles today
After that, nothing for years, but I never forgot it!
My first instinctive feel of pussy, except at birth, was a dog's.
Eventually, I got into bestiality, and mostly could only find women getting fucked by dogs - still enjoyed watching it, but it was not satisfying.
Then while I was a teenager, starting to get horny and learn about sex, I found one grainy video of a man fucking a dog's pussy, and it spurred me to start fantasizing about dogs, though I still liked human females also. I dreamed about how I could get close enough to fuck a dog, but it never came to be, until years later - after I had sex with human females, and started renting my own room not with family.
It was something I had long dreamed of, but not seriously planned for - and it was a surprise to the people I lived with, lol, which caused some tension, but they forgave me. Even if I had to move because of that, or give up the dog, I would have chosen the dog. She was my first non-human sexual partner, for more than just awkward dry fingering.
She was a rescue dog, something like a pitbull lab mix, and I admit my motivation was selfish at first, but I treated her with the utmost kindness, and we grew very close. I started fingering her on the first night - but first made her a gourmet meal. I usually shared my food with her, instead of just feeding her kibble. She loved the smell of my dick, and would lick it while I fingered her. After a few months of training her pussy, while basically doing sixty-nine (fingering, stretching, slowly increasing her capacity - while jerking off and getting licked), she was finally ready. We started having sex almost daily, sometimes more than once a day. I loved that dog. She was my "first wife" though with nothing on paper of course. We went basically everywhere together, until she grew old and eventually passed on. It was very emotional, not only physical, and we were seriously almost never apart, for years. My only regret is that she was already spayed before I got her, and we were not able to raise any puppies together.