The Hypnotist is relatively heavy at 12.9 oz so it may not hold altitude on its back except in even higher winds, start high and you should have plenty of time though to try a few things.
First make sure you've given slack with your off hand before hitting the Lazy S, tension on the opposite wing will bring it out. I've also found that hitting your Lazy S attempt as soon as it goes on its back and the nose is still very deep is more reliable on kites that will fall out of a Turtle quickly. Alternately another small wrist pop while on its back followed quickly by slack may sit it deeper too.
I don't recall, does it have two bridle settings like some Prism's? If so you might try the alternate setting to see if it'll sit any deeper, that'll help with the Lazy S and may help to retain altitude while on its back too. If it then ends up being stuck on its back then just do a Lazy Susan, they usually go back to nose up after a rotation