9259 is a popular happening bar in Shinjuku (Tokyo). It is a slightly different HB experience, as they have these interesting shows, and that can be more of a focus than swinging.
It’s a kind of peculiar were you see people walking around naked at times and outside of “designated play areas” including sometimes the staff.
In fact, some Japanese girls ladies come to check out the guys package size to see which one she wants to have sex with. However, as mentioned, there isn’t any prerequisite for other members to be naked. It’s entirely optional.
For single guys, 9259 can be a hook up spot (though entrance fee is a bit expensive) to meet sexually liberated women and to include “test driving” right at the “showroom”. For single women, it’s all nearly free fun, minus their ID registration.