approaching bi-couples

It's not really a topic I guess, more of a question for bi-couples. I went to a video lounge room in the Valley in Brisbane last week and got my eyes opened and had a great time. Do many couples frequent these sorts of places - I saw some couples come through but they didn't stay for long mostly because they got continually stalked by all the guys. What's the best way to approach a couple in this situation?? I'm OK looking but in such an environment it would be understandable for couples to just walk out because every guy is jostling to stand out. Any hints??