To pull a face that is overtly and knowingly smarmy.
'I just smarmed that girl. She wasn't happy.'
A smarm is usually employed when someone has told you something that they believe is interesting. You can show your disdain for this person by smarming them.
Thus a "smarmy" person is cloying, over-ingratiating, oleaginous ("oily"), close, and over-familiar.
"Who was that man who pretended to know you so well?"
"Oh, Kenneth. Ignore him. He confuses charm with smarm."
"Ahh... I'm feeling all smarmy now."