A vocal substitution for the common arm movement associated with trying to get another's attention.
Common male practice when in a loud bar is to nudge one's friend with an arm and point, either with a raise of the chin or casual hand motion, to draw attention to an attractive women as often vocal communication is difficult.
"Yo, check out that nudge."
"There were mad nudges out last night."
"The party would have been better if all those jibbles had been nudges."