Reflex T-Rex

The instinctual response to bring one's arms up to ones's chest comically, much like in the manner of a T-Rex. This is done in response to an extremely awkward situation in which one is left speechless and can only resort to reflex t-rexing. This reaction is also applicable to when someone you find particularly obnoxious comes into the the room and you signal to your friends your dislike of said person without giving yourself away.

"Dude, she asked if i poopjasterblevomulate"
"WHAT? what did you say?"
"I couldn't say anything. I just reflex T-rexed until she left"