This Kon Muay use for defense the straight punch at close quarters by let the punch pass over the head and throwing the punch at the chin.

The attacker walks in and throws the left punch at the defensive’s face. The defensive bends the head down, let the punch pass over while steps forwards with the left foot. Tthrows suddenly the left punch to the attacker’s chin. If the attacker throws with the right punch.

Do the same as above in the opposite directions.