Do any of you guys practice the Nikka jo variation where you cut toward your knee drag and uke toward you? That one can make you wet your dogi.
My teacher shows this, as an option in certain situations. He also teaches that you shouldn't depend on pain compliance for nikkyo to work, so go figure.
"Drag" is probably not the best term, though it's inevitable shorthand. It's more like: make a hole, lock up uke's structure so there's no where else for him to go, and the more he falls into it the more hole you make. It looks a lot like dragging.