A face made, usually by males, when they see hot women. Their sexual desires are clearly written all over their face when they want sexual intercourse with a certain female 'victim'.
It consists of a strain in the face, possible teeth gritting or lower-lip biting and a dark glaze over the eyes as they imagine having their wicked way. A sweating brow and or top lip is usally evident.
John: Hey! Harry, stop giving her the pest face.
Harry: I can't help it my balls are the size of watermelons.