straight elbow vs hook or boxing guard

https://www.youtube.com/watch?v=-7J1dmnnabQ
Muay Thai Using the Straight / Spear Elbow Tutorial

on the hooking side you put up your hands to comb hair (straight or spear elbow)
-you either step in with elbow as he throws hook
-or you can catch/block and then step in with elbow

or if you see boxing guard
-step in with straight or spear elbow