Lip quiver 

To cry

or, to nearly cry

or, to try not to cry but come very close

She got told off by the boss and went off for a lip quiver.

When he said I was his best friend I had a little lip quiver.

I didn't burst into tears but I did have a quick lip quiver.

Lip quiver by TheWeirdnessSymposium February 26, 2009

Quivering Lip 

The female perineum or taint. The area between the brown eye (balloon knot) and the whispering eye.

Lick my quivering lip, it gets me off.

Quivering Lip by Pistol_Pete12 January 24, 2011