Do you use a breast collar when you ride? It can help with sliding back. I don't ride without one on the trails. I can do without it if I am just plunking around the house, but on the trails...well, lets just say having the saddle slide too far backwards is NOT a pleasant experience for either horse or rider. Fortunately, the mare I had at the time was a good girl, and I didn't get kicked. It was sure embarassing having to re-saddle her with all my companions standing around laughing at me!
Plain Old Dee, horses Dancer and Rain I believe in dragons, unicorns, good men and other mythical creatures!