You're a nobody today, 'cause I wanna have fun by riding you, my little pony! Now start to move, sissy! You act like you're in a circus act, bitch! Get your ass moving, or otherwise I'll beat the hell out of you with my whip! You'll carry me now one round after another as long as I want it to!
Adriana's severe voice guides the loser through her ponytraining. While she's sitting on his back, she gives him pretty clear commands which he has to follow. No matter if he has to move forwards, backwards or sideways, he has to perform for every single command!
For Angelina it's just normal to train her slaves to be a human pony during their slave training. As a young dominatrix she knows exactly how to make submissive slaves follow her orders. Just like this slave should feel honored to be allowed to serve this goddess as a pony. And when her pony can't take it anymore? Then Angelina will just make it move with some kicks!