Volunteering at the Vet (part 1)

I was 16. I was being punished by my parents because they caught me fucking my step-cousin.
So anyways I'm being made to volunteer at the local vet twice a day I had to go tend to the animals that were boarding there.
It was a Sunday morning and I went to start letting dogs out, feeding and watering them. Then I'd move on to the donkeys that the vet kept as pets in the back fence.
There was one Great Dane. Her name was Emma. She was in heat. Her black pussy was swollen and she whined and backed her backend toward me as I stood in the fence watching her.
I sat down on the bench and she backed her hind legs in between my legs.
I laughed and pushed her away but she came right back. So I teased her and poked her swollen pussy with a finger.
That triggered me. Her pussy felt just like a humans pussy.
I slid my finger back into her swollen pussy. It was hot, wet and tight.
I slid another finger in her pussy. She began to hump her hindquarters.
I slid my fingers in and out of her pussy.
My cock was getting hard. I looked around and then I decided I'd go to the barn, if she follows them she follows but being out in the back yard in bright day light was too risky.
So I pulled my fingers out of hey pussy and they were wet and slimy. I held them and Emma started licking her pussy juice off my fingers.
I walked to the barn and pulled my cock out over my shorts. I stroked my cock and watched Emma back her pussy against me.
I lined my cock against her swollen wet pussy and I pushed my cock all the way it.
"Holy fuck you feel good". I moaned as my balls were tickled by her hair. I pulled my cock out to the head then pushed balls deep again.
I grabbed her backside and pulled her as I thrusted again and again.
I moaned "fuck girl your pussy is good" and I thrusted harder.
She was panting and keeping her balance as I fucked her pussy for several minutes.
I grunted loud and pulled her back against my thrust and I emptied my balls into her pussy.
Once I sit my load into her I fell back on to the bale of hay.
Emma turned and started licking my cum that was leaking from her used pussy.
I smiled and thought "of this is gonna be a fun summer after all".