We were here last Saturday, just in the city for the weekend. From what we'd dug up before the trip, this looks like the best club in Prague. We tried to find out more about other clubs too, but not everyone replied to our request for info.
The club is about 25–30 minutes by taxi from the Old Town. It's nicely fitted out, modern, and clean. Ladies can keep their own shoes on if they wipe the soles; men use slippers or go barefoot. The whole club is carpeted except for the bar. There's even a little buffet where you can grab a small bite if you get hungry.
The play space isn't huge, but big enough to fit plenty of people — there are open areas as well as nooks for couples who don't want interaction with others. There's also a small dark room with gloryholes and other gear for the more adventurous tastes.
A reservation is recommended any day, and on Saturday it's a must. We arrived at 10:40 p.m. and it was nearly full, around 25 couples. The ages varied, centered around thirty-five — and they were attractive regardless of age.
The staff speak English and are very pleasant. It helps to speak slowly and patiently. Plenty of couples had decent English, but we didn't get into deep conversations and didn't need to.
The etiquette for making a move is a bit different from back home in England: indicating a touch is fine — they give consent by not removing your hand and not pulling away.
Payment is cash only. For entry, a bottle of prosecco, and water we paid 2,400 Kč. Bring local currency to make it easier. Budget 2,000 to 4,000 Kč depending on how much you drink.
All in all a great evening — even though we were a bit shy in a new club, and yes, we got involved with others too.
Hopefully this helps others heading to Prague. We have no affiliation with the club; by the way, it was hard to gauge the turnout, because even on the best-known swingers sites there are no forums where people signal that they're coming. It seems most people just show up, enjoy themselves, and leave.