Join Date: Nov 2011
Location: Central Oregon, USA
If your horse has an uncomfortable trot to sit, you may find it is actually easier to post to! And I would recommend using a saddle before bareback to learn, but that's personal opinion. (I tend to bounce around a bit more bareback).
Indeed, do not pinch your knees in, instead, use your whole leg. The horse should post YOU out of the saddle. It was a mistake I made for many years when I was starting out, putting too much effort in and standing in the stirrups each post.
Try closing your hip angle ever so slightly and allowing the movement of the trot to raise your bum a bit. Hold it for the step and gently sit back down. Always go with the beat of the horse when starting out, and ideally rise with the outside fore leg (but to start out, just getting a hang of it is great!).
If you can get someone to lunge the horse while you figure it out, it is a great help! Then you can concentrate solely on posting.
Best of luck!