Originally Posted by apachewhitesox
About moving sideways under saddle he only turns no moving sideways.
that's a bit of a problem. Your trying to "push" him out onto a bigger circle while maintaining the bend of the left/right circle (a sideways movement)
At best you won't be successful in fixing the issue of him not bending in a circle, at worst you'll desensitize him to rein aids by conflicting those aids with leg aids which he thinks mean steer. I'd suggest you speak to a trainer IRL. With my personal horses I don't do much sideways either, but sideways is a great thing to do to loosen up their ribs and flexibility, and really helps getting them to bend appropriately when circling.
As a horseman i'd recommend you do lots of sideways and see if the problem persists. Sideways is just a combination of yielding the forehand, and yielding the rear quarters at the same time, so seeing as you know both of them, be creative in getting a sideways action going.
What I do is put one leg on, then if they yield the hind, I immediately follow the movement with yielding the fore. And if they yield the fore (more likely), I immediately follow it with yielding the hind. Eventually the horses get it that if they yield one more than the other it's just going to end up with me asking them to yield the other one then resting for a short while, so they yield both at the same pace. Though there are many tried and proven methods.