As a "swingle" I have gone to a few different places in search of a true swinging experience. I have been burned by going to places in the city which are essentially a "party" with a "cover charge" where they put you in a room, have you undress with a towel and then socialize with a few ladies for you to choose from......IMHO, NYC is a waste of time for "swingles"
But I have been to LI Manor and if you go as a single guy, be ready to be able to go a few times before you have any luck. While it is true that there are mainly couples there, if they like you, yo uare welcome into the "circle of trust". Once you are in, you can show up every week and start dancing with any woman in the place and then make you moves. If they like those moves, then they may ask you to party with them after they leave the Manor. I have gotten lucky there a few different times and it was a blast. There have been several parties on Long Island that I was lucky to get into, so there are some real swingers out here. You may want to check Roberto's too.....I haven't been there, but people at the last party talked about going there.
Hope this helps !!