In English mean the upper-knees

The upper knees are used for the attack that’s close to the opponent's body. Can use both of the knees such as pushing the right knee up to the opponent's chest in order to make a gap and then throwing the left knee to the opponent's abdomen while holding tightly the opponent's neck with both hands.

To protect
Use the hands to guard the chest and abdomen

To counter
Try to lean back and throw the straight punch to the opponent's chin.