I couldn't help it; he was one of the hottest little fuckers I'd ever seen. He walked into the changing room with a bigger bear - I assumed he was the kid's father. They were talking about where they could go for lunch as they stepped into the curtained off changing stalls. The kid chose the one right next to me, his dad one farther down. 

Being a horse, and a rather big one at that, I managed a few peeks over the top of the curtain. I usually like them chubby, and while the kid wasn't exactly a porker, he did fit the bill. My shorts were painfully tented as, unnoticed, I watched him strip down. I nearly died when I saw the little speedo he started to put on. I couldn't bear the swimming trunks any longer - they were really digging in. I let them fall to my ankles. I figured I'd try to shoot off a quick one while I was in the buff, but there was a slight miracle of sorts; the kid couldn't get the speedo to fit over his soft, shapely-looking backside. 

The kid's father asked if he was ready, and the kid  said he'd catch up, Before I knew it, the older bear was gone. It was just me and the kid in the changing room. I watched from above as the little bear tried in vain to pull the back of the speedo up his furry rump. I couldn't stand still any longer; I was throbbing. I lifted the curtain dividing our stalls and slipped in. The kid turned around and saw me.

"Sir, this stall is occu...."

He caught sight of my dick standing tall as hell. He stood there, eyes wide, like he didn't know what to do. I took the opportunity.

"Don't worry, kid. I'm here to help with those shorts."

I grabbed his ass, easy as that. It was as soft as it had looked, and gave in easily beneath my fingers. I had a hand on each buttock, and the kid was still frozen in shock. I ran a thumb up to his fuzzy little tail. God, it was so soft. The base of my cock slotted into place between those supple cheeks. It was a bit too big to be enveloped by his warm ass, though. It stood up the length of his back unti its head, flared and dripping, dampened the fur by the kid's shoulderblades.

I let my fingers slip down beneath his speedo, and slid it farther down his ass. I leaned forward and breathed down his neck.

"S... sir... I...."

I whispered in his ear.

"What's your name, kid?"

"C... Colton, sir...."  

"Well, Colton...."

I slid my cock down his back, and pressed its head firmly against his tail.

"I've been waiting for an ass like yours, kid."

I pushed him forward until he leaned against the back wall - then I pressed into him with all I had. After a moment of resistence, his eyes went even wider, and my head slid right in. The sound he made was low and harsh, like someone punched him in the gut. He made the sound again, but drawn out this time, as I gripped his hips. I was panting. I pushed forward again, and managed another few inches. He cried out louder this time. He managed a sentence between grunts.

"Oh, god!"

I pushed even harder, and the noises grew more insistant.

"Eeeeaaaooooh God, no more!"

I wasn't even half in.