Ive never had one while the few times I have rode a horse. Yet to further this answer, I have had multiple orgasms on a motor bike. One day while riding I had my hips tilted forward a little more than normal because I wanted to secure myself building up some speed for this little jump by my house. So while riding up to it I realize the vibration from the revving motor is tingling my clit and pussy in a way that was intoxicating. It almost became a bit addictive because it was so easy to just position myself the right way and just literally ride myself into ecstasy. I miss my bike and riding it out in the desert by my house, just alone time letting go and pleasuring myself. Became very therapeutic actually. But yeah, I use to have myself orgasm a lot riding my motor bike.