Bad Inside and Outside Hands
In Chi Sau we have Taan Sau 攤手 and Bong Sau 膀手, which are inside hands. We also have Fuk Sau伏手, which is an outside hand. During rolling hands we need to know how to change from the inside Taan Sau to the outside Fuk Sau. We also need to know how to change from the outside Fuk Sau back to the inside Taan Sau.
While we are changing we must keep the motion smooth and safe, then our opponent will not notice too much and we will not be hit. However, some students like to stay on the outside most of the time and every time their opponent changes to the outside Fuk Sau, they will immediately change back to the outside themselves. They do this so much that it becomes a habit and this is a bad hand. It is the same as some students always trying to maintain the inside Taan Sau and Bong Sau. They also feel it uncomfortable when the opponent takes the inside and so they change immediately.
Any habit of keeping the inside or the outside hand most of the time means there is a weakness in our Chi Sau. This weakness will mean that has skilled opponent will use this and hit us. We need to overcome our weaknesses during Chi Sau training and not try and hide them.