One reason this is difficult for followers is because, for the first years of their tango life we tell them over and over again that they respond to what the leader does. Perhaps, they may even embellish a little on their own. But never, do they move the leader. Except, of course, that isn't true.

For Followers: Have the conviction to keep your leg connected with your body, so that, if the leader moves your body to the side, your leg must follow. Even if his foot's there.

For Leaders: You can help the follower, especially at the beginning, by making your foot like a gentle wind. That way, she doesn't even focus on the foot but on what's happening on top and the drag happens by itself.