There are six types of Tui Shou in the Original Yang Style curriculum. These are essential in getting a deep and dynamic understanding of the underlying principles and form applications. When you practice the form, you are free and unhindered, when practicing with a partner, you have to learn to adjust your movements without losing the principles already acquired.
The partner exercises, while not a sort of fighting or competition in themselves, are also a preparation for Tai Chi Chuan as self-defense.
These forms of pushing hands in fact have nothing to do with "pushing" away. It's about sensing and answering by following.
The various partner exercises of the the Original Yang Style:
• Single Push hands
• Double Push hands
• Flat Circle Push hands
• Ta Lu Pushing Hands
• Ta Lu Form
• Free Push hands where all the movements of the solo-form and the weapon-forms can be used.