I've sort of seen two schools of thought on this that are almost entirely opposite.
The first holds that before you even begin doing the shihonage you should have uke's elbow and wrist cranked enough so that their hips are thrust forward and they are up on their toes. Make sure they stay like this as you pass under the arm and, trust me, they won't be going anywhere. I see that a lot in ASU and AiKiKai dojos.
The other version (more 'seidokan') is best understood by letting uke grab your finger instead of your wrist. Now try to do shihonage without ripping your own finger off. You'll find that to do it you must find a path that brings uke's hand to their shoulder without giving them a lot of excuses to pull on your finger or twist around. This involves a very light touch.
Of course, one would hope that when you practice shihonage with beginners you go quite slowly, giving them ample time to think about their options and do all kinds of crazy things. "On the street" (wherever that is), one suspects that both you and your 'partner' will be moving at a more realistic pace.