The word "mere" is normally used in conjunction with an opening and closing of ones hand with the palm facing up, in a "come here" or "gimme" fashion, similar to what a child would do when wanting something.
It also can be combined with right meow to emphasize.
It originates from the incorrect pronunciation/combination of "come here". It was created by a young child just learning how to talk.
Trying to get the bartender's attention at a bar: "Mere, right meow!"
Man wanting his woman to come to the bedroom for some late night activities, with hand gesture: "Mere!"
Woman wanting a hit off of her man's cigarette, with the opening and closing of her hand directed at the cigarette: "Mere!"
Is usually accompanied with or followed by some sort of hand gesture.