Quit horsing around

The picture had been of four guys dressed in tight rubber, with full face horse masks and hoof gloves and shoes. All four were in full harness and pulling a small carriage. I blinked the blurryness away and found myself in a stable. I was locked in a horse stall and there was straw underfoot (or underhoof I should say). Curious I glanced around, noticing three other ponybois in the stable, each with their own stall. In the middle of the stable was an empty carriage like the one from the pic and hanging on the posts next to each stall was a bridle and harness. Before I could examine anything else, the stable door opened and a large breasted figure in a tight leather corset and thigh high boots entered. For a moment I thought it was the carriage driver from the pic, then I realised she had the face of...