I'm intrigued as to just how important is someones reaction to being gunged, what is the best way for someone to react for you?

A slight smirk of humiliation and reluctant enjoyment, ie. they just got owned but are taking it with good grace.

Undeniable pleasure and unmistakable arousal!

How about closed eyes and a blissed-out smile?

What about squealing, squirming and pretending to get upset?