I had a mare mule with only one eye who regarded her fantasies as extremely important.
If I approached her sexually from her visual side, her tail would clamp down. She was having nothing to do with a two-legs.
But if I approached from her blind side, that tail would raise up and swing aside. It was all "Ooh-la-la!" and "Keep doing that, it's wonderful!" All she had to do was turn her head had she wanted to see who was behind her, but she never looked back until the fun was over.