You turn to to run, but the dildo moves too quickly. You get only a few steps before you feel something dart up your pant leg. You quickly unbutton your pants and drop them to the floor, stumbling, as the magic phallus crawls up your leg. It's too late, the dildo is in your underwear! You literally rip them off. The dildo presses against your anus as the the torn fabric drops to the floor.
"No!" you scream. And then it's inside. All the way inside.
The dildo painfully stretches your butt hole. You reach down to pull it out, and you feel it move out of your body. You've almost removed it entirely when it pulls itself back in. Then it starts moving in and out, just as it did with your mouth. You moan in pain as the dildo fucks your ass. Fingers flailing, you reach for it again, but it's moving so much that it's hard to get a good grip. The pain is intense.
Then you start feeling something else. The pain is diminishing and pleasure is taking its place. You feel your dick start to stir, and looking down, you watch as it slowly begins to stand erect. With a quaking hand, you reach down to touch it, and you shudder as pleasure floods your body. You're actually enjoying having the dildo in your butt. Does that make you gay? Does it matter? You have a magical horse dildo in your anus after all...