This trains the principles of settling the body and advancing the body, the method of absorbing in the body core and hips, the principle of controlling the opponent.
Partners stand facing each other in turned horse stance, with wrists connected. Push towards the face, or chuanzhang towards the eyes. Extend and release the shoulder. Defend by turning away and sitting back. Use the body to control, not the arms, turn the whole body to get the deflection. Set down into the stance, and push from the legs, but keep the power from the front leg. Keep the body vertical.
This can also be done with the leading feet placed on the outside of each other. This trains the more specific bagua way of doing things more sideways than straight on.