We love narrowboat holidays, have done the Llangollen trip and Kennet and Avon down to Bath.
Havn't used it to swing yet, but it seems a very natural thing to do.
Me and the wife were only saying yesterday what a good idea it would be if we brought a boat and made it into a swingers venue. Even came up with a name for it. Argy bargy partys
We had a meet on a couples narrow boat. It was lovely.
There was a gentle rocking as another boat went past. Gave the guy steering a right eye full too