i dont think i could answer for the whole of the male population, but in general:
i would think what would occasionally work is if you mentioned something that is to do with one of their interests/hobbies (for example taste in music), that would grab their attention. however how do you know what they are into?
if you walk past them give them plenty of eye contact and make it obvious. then once youve walked past them look round at them and theres a chance they'll be looking towards you still if you made it obvious enough in the first place. then like fluent in lies said, flash 'em!