We went over some kick defenses towards the end of class just the other day. My conclusion is this, real pain is Kotegaeshi applied to the foot... Ye-ouch!
Agree with you on this. I like to caution you that this technique should be done with care to avoid serious injury to the Uke.
A long time ago. I had a friendly (at least I thought it was going to be friendly) sparring session with a TKD black belt. During the match, he thrown a side kick which I managed to trap between my left elbow and my right hand. He was hopping on one foot trying to keep his balance. As far I was concerned the match was over and was about to release his foot when I saw his right fist coming in an arc towards my face. I had got both my arms on his leg and there was not enough time to meet the strike with my right arm. By instinct, I turned his foot (still caught between my elbow) downwards. I believe that the direction of the foot turning coupled with the counter direction of his swinging right arm and hips must had torn some ligaments in his knee. He was out of physical action for six months. I felt awefully bad for his injury.
The Uke must really blend with you on this technique to avoid serious injury to the knees.
That's my free advice.