You can show up alone - but understand that there will be alot of men circulating hoping to hook up with one of the very rare single women or join a couple in a menage a trois or even a gang bang / bukkake event! No means no @ Aquarius including the gay males who will approach but everyone respects no!!!
I have been a couple of times - if you are into BDSM there is usually someone tied up down stairs, there are voyeur hole drilled into some of the private rooms downstairs, there are showers, sauna ....
I went to Aquarius for the first time on Thursday. Very sad place. It was dark, empty, and dingy and consisted of a group of men in towels slowly walking around with a dazed look in their face. The scene made me think of what the inside of a mental institution must be like. The only action I saw take place was a BJ given in some dark corner.
There were two lone women there, both very overweight and unattractive. Quite talkative and friendly, however.
I saw two couples, one was attractive but obviously uninterested in any male advances. The other was early-50's and unattractive, talkative and friendly but looking for a single female (like most of the other sad-faced towel-clad room-walkers).
Generally, a very creepy experience. The only reason I'd go back is if a bombshell stripper or Playboy playmate invited me...lol. And even then I'd be hesitant.
Aquarius is a bathouse if you haven't noticed so most of the clients are gay or at least bi.
I've been there a few times by myself and with a female friend.
Don't get your expectations up to high and you'll be fine. I've had a m/f couple invite me to their room so he could watch me bang his wife. That was fun. Finished and showered and left.
With my female friend it was ok but at the time no one was there that was suitable to join in. It can be quite the weinie roast but that's to be expected. There has been other good looking couples but the times I go there it's by myself and there not around when I have my female friend.
The good looking couples tend to be a little more picky. Understandably so. If your looking for a couple to join it's possible depending on your standards. It's always possible for a guy to join in as there is no short supply of them. If your looking for the voyeuristic experience you can have that too. There wouldn't be a shortage of people watching.
Go and enjoy yourself. What's the worse that would happen? You see some guys in a towel. Nothing worse than going to a gym. Except they might hit on you. Maybe there will be a good looking couple you can hook up with.