Hobby? Lifestyle?
We picked hobby, mainly because the time we actually spend doing it is very limited. Much like a hobby.
We do consider ourselves "lifestyle" though. It affects everything we do as a couple. We go to "straight" bars. We're looking at potential couples & singles. We're at the mall, we're looking at other couples and singles. Generally discussing taste and whether we think the other person(s) might be interested. (We know the answer already

)We watch TV, we commonly joke with each other about people on TV we would like to have. The joke part usually runs between whether we would let the other watch/participate, or make them wait in the other room, while one of us done some really freaky things with this party/parties
We do manage to keep things very seperate when among family and (certian) friends. But rest assured, there is little doubt when you meet us (in a "regular bar"), that something is just not quiet right/normal.