Not in the mouth 

Used awkwardly -- and ONLY awkwardly -- after something you've said to/about the opposite sex (or same, if that's how you go about) could be mistakenly taken into a flirtatious or more-than-friendly context. Replaces "but not like that" in most cases.

Basically:
"I'm completely positive towards you at the moment, but not in a way that I want to shove my crotch into your face."

Dude 1: Yo, do you like her?
Dude 2: Yeah . . . but not in the mouth.
Dude 1: What the HELL does that MEAN?

Not in the mouth by RJF75 March 5, 2009

Not screw a gift horse in the mouth 

Don't screw a gift horse in the mouth is akin to the time honored phrase "don't look a gift horse in the mouth" which basically means don't be critical of gifts or people might not want to give you things in future.

This promotion is right up your ally Smith, now lets not screw a gift horse in the mouth!

Not screw a gift horse in the mouth by bhnicfh August 28, 2011