Re: uke spinning out of shihonage
This is a common problem with shihonage. Often it occurs during static practice, where uke's balance hasn't been taken.
* Make sure on the "draw" that uke's arm is fully extended and their weight is on the lead foot.
* Don't raise uke's arm over your head, use your knees to go under the arm. Keep uke's wrist rested on your forehead as you begin to move under the arm.
* When passing under the arm, make sure uke's arm, in particular uke's elbow, always remains in contact with your body. You can easily switch to a arm bar if something should go awry during shihonage
* Should uke turn out, follow up with another shihonage but drop the level of the technique lower. It seems beginners have the knack to do that turn out. After completing my pivot, I would change elevations and drop to one knee up like in hanmi handachi and apply shihonage "cut" from there.
For what it is worth, have your instructor evaluate your shihonage, he/she can help better than anyone online can. While the online community can give shall we say inspiration, run the "inspiration" through your instructor for proper guidance and execution of technique.