Friendly Switch."As part of your movement or as a 5-foot-step, you can move into the space occupied by an ally of your size or smaller, which displaces the ally into the space you just left".
Today I had a really hard problem with one of my adventure character player. He makes his 30ft movement, steps into the wizards space and he wants to move the wizard, not into the space he just left (5 feet before the wizard), but into the square he left at the begging of his movement, 30ft away.
I didn't let him to do it. Because the "space you just left" I believe means the square 5-foot-step near your target. What do you think?