One who is lacking in proper flirtation skills, and so must resort to behaviors a 3rd grader would partake in to display their attraction, consequently causing all of those who witness such patheticness to gag or remove themselves from the premises.
"Did you see that guy in the study lounge? He was such a nerdflirter! He kept on poking that girl in the arm with is finger and saying, "No, YOUUUUU..." and then she'd just giggle and do the same thing back. I had to bust outta there before the gag-factor triggered a lunch revisit."