The biggest challenge for me when interacting with girls, arguing or when being exited, I end up reacting, acting defensive, speaking quickly or locking up.

However, when I stay calm and non-reactive I'm able to have meaningful conversations, argue my point and respond in clear non-defensive manner. I would think this is what the author of NMMNG calls "her behaviour does not affect mine". This only happens when I conciously think of doing this, which is rarely.

What's the best way to "remember" of staying calm..how would one cultivate/practice this behavior?