Rou Quan is a favourite form of mine because it mixes internal and external together. It may look gentle but that's because the strength is hidden inside the movement. It can make you quickly tired because you need to stay in the stances for a longer time. Sometimes the movement is soft and at other times you need to use power but this power is not the same as when you use power in a kung fu form, it is a special combination of mixing internal and external.
Rou Quan is a famous Shaolin form, which is independent from all the other forms. One of the reasons for this is because it has some famous traditional techniques hidden in the movement. If they are not pointed out then a person may practice the form and be totally unaware of this. At the Shaolin Temple, Qigong practioners practise it, as do kung fu practioners because it perfectly complements both internal training and external training.
It needs more space than Qi Gong so try and go outside or to a park and run through it two or three times a few times a week. Once your body remembers it you can let go of thinking and it will tap into the innate harmony in your body. Not only qill it improve your Qigong and Kung Fu but I guarantee you will feel peaceful after practicing Rou Quan and more ready to face the day.