I have spent an hour trying to find the old COTH Forum posting that taught me this.
The “rider’s push-up”, it was in a topic titled “Working on a new jump seat and hating it” from many years ago.
Get up into two-point. Then, while your butt goes back, bend at the hips so that your chest touches the crest of the horse’s neck, keeping your head up, face vertical and eyes forward. Repeat a few times if needed. Avoid using your hands for support if possible.
I introduced this exercise to my riding teacher and she usually has me do it two or three times in a 30 minute lesson. I have MS, I get muscle spasms so my body does not work right, and this is the only thing I have found that “unlocks” my hip joints. After I do it I find it SO MUCH EASIER to follow the horse’s back motion with my seat.
She also has other students do this exercise if she thinks they need it.