This is rarely seen. U can put a search for this special kick and see while other types of kicks get discussed or showcased, this one can hardly be seen. I am using my thighs to kick. As you can see, this is a rather high. Here are other points you may wish to note about this special kick:

• It is a high kick. 
• It involves a jump/leap into the target. 
• It is a close kick. You have to move into your target, hold him down for this kick. If you are stronger, you can use one hand, as I am seen doing on-off in this video. Otherwise, hold with both hands to bring target into you and for you to move into him. 
• One hand may be held off, as I am doing, for a punch, if you kick meets the target. This would be a double-whammy! 
• You are aiming for the side of the body. The ribcage/chest. If target slips, then the face can also be hit. 
• In the end of the video I am doing reps: for this you need to have great cardio practice. Reps with such kicks can be devastating and completely wind the target. Obviously, to do reps the way I am doing you need super practice. And tremendous stamina and breath strength. 

Other points, not related to this kick, but to practice in general: I am using a hard-barked tree for this practice. 

This is the way I learnt it in my village, as a child and teenager. And it has made my practice super tough. You first start with practising on your teacher's pads. Then you may practice on plantain trees. Their stems are smoother and hardy, but still not as tough as this one. Then, after perfecting your practice there, you may move to such trees with hard barks. Later on, you may even practice on walls, as I have shown, in my earlier videos on shin kicks. For that sort of practice, you need to be fantatic about Muay Thai practice!!