Paging Plan9, we need your assistance in operations, repeat Paging Plan9...
Knowing me I would walk up to her and say say in the most melodramatic way, followed by deadpan humor "I have feeling, I'm talking to you aren't I. Wait is horny a feeling... ? it really doesn't matter, you want to get coffee after class ?"
That would be a "see if the girl has a sense of humor and can carry a conversation" test, if she says no I figure it wouldn't have worked anyway and if she says yes
*disclaimer* The following opinion involved very bad ideas which should not be followed by anyone who is slow on their feet or lack a good feel for humor and people... infact it simply shouldn't be followed by anyone. Seriously, why are you reading this... horrible idea