You watch as your own penis began to grow, while still inside your pants, but just then you noticed that it became so long, that it ripped through your pants, and underwear at the same time. You couldn't have handled such a big erection in your own life, but you felt it building up inside you as you sat there by yourself.
Your own testicles began to inflate, as you laid there, and turned black as you also notice from underneath they were connecting to your butthole as they moved below it. The rest of the penis became long, and pink, while the shaft changed to a more equine state. You now had the penis of a horse, which was so long, you don't even know how it will fit inside the toilet after you stick it in the toilet later that night. However, you found that your penis wasn't the only thing that was gonna change.