There is a wealth of material that we do in class but which has no obvious home in the syllabus; exercises that are not precisely conditioning, nor do they belong to a specific historical system.
One such is the stepping drill, which shares a some DNA with push-hands, but is not, and some with wrestling, but is not. The idea is that the two players face off and try to make the other move a foot. Once that is going nicely, each player may be allowed a single step, to use in attack or defence; the second step loses the match. This is suposed to be done with minimum physical force, and in a spirit of friendly competition.