Refuse, or don't say anything

You will be trained as a mount
Hours later, a goblin takes off your blindfold, revealing the crude training paddock they've prepared. You are forced to wear leather ears, a tight bridle with a bit gag to replace your ball gag, and a saddle strapped to your back.

But worst is the tail, it's not just an ornament, it's a long string of anal beads that makes your ass feel full and it's stripping your dignity away. They also put a chastity device to avoid vaginal rape from other goblins, they don't want pregnant mounts.
The training master licks your ear and says. "Lesson one, you move when I say move!"

The exercises are a terrible torture. They force you to trot in circles for hours. When you stumble, he makes you start again. If you scream, he laughs and adds weight to the saddle. And finally, if you collapse and you don't want to continue, he whips your ass until you start.

He breaks you down, then builds you back up as something obedient, something useful for them. With each passing day, you forget about escaping, and you just want to avoid pain. When you are finally broken, the brand you and you start to serve.

You finish your days serving the camp like a strong, obedient mount.

Bad ending
Well trained ending