When you look at what constitutes a "gay" or "straight" lifestyle - you are looking at how people view themselves - as masculine or feminine, who they are generally attracted to (not just individual people, but either male or female, or both) --- if someone wants to experiment or the situation just leads to it or whatever for a 1-2 x in a life experience, its not really a "lifestyle choice" that you could label bisexual and have that person carry the label for the rest of their life. Esp in this day & age when this stuff just seems to be more "acceptable", people may be more likely to have that little curiosity or whatever and not get all hung up about it. So I think for that gray area you can call it "bi curious". Are you a straight up Conservative or Liberal? There's always someone who might try the other side just for the experience, to explore it, becuse they were drunk, whatever. But their general tendency may be all striaght or all gay. The lines just aren't that strictly drawn by both nature and by situation.