When I went to my first seminar with Doran sensei in spring of this year, he used the picture of "offering a cup of tea to uke" for a part of nikkyo tenkan - he also pointed out that one should never spill the tea but instead be careful to keep the cup upright. I loved that picture and it works very well to make sure that uke´s writs is under total control all the way until the lever/technique is applied (especially with kids).
Seems like there are quite a few food analogies around