I would definitely recommend Vera Playa as a great option. The swinger club has sadly permanently closed down but there is a swinger friendly bar with a couples-only play area next door to the where the club used to be.
I've only ever stayed in the Vera Playa Club Hotel which is a nice enough place with large grounds and a lagoon shaped pool. I've not had any action there personally though there are plenty of couples and bi/gay guys discreetly wanking each other off in the jacuzzi. There is a life guard who does get verbal and stroppy if it goes beyond this as this is a family friendly/naturist hotel with children around so be aware and respectful of this fact please.
Vera Playa has a naturist urbanization and a large area of the beach is naturist too (not the whole beach as someone says above). This mean anyone is allowed to walk freely naked around this area but you need to carry a towel/sarong or something similar if you plan to venture inside some establishments that serve food/drink or if you intend sitting down whilst in there. Sex on the public street or beach would likely carry a similar penalty as anywhere that was on a non-naturist urbanization.
Gran Canaria is by far more swinger friendly but is seasonal as many swingers clubs close June/July and don't reopen until September. The activity in the dunes has dramatically reduced recent years as the authorities have clamped down because people were using the protected area and not respecting the restrictions. I think that area is policed more and heavy fines handed out if caught. As I have not been for several years it is definitely worth getting more up to date knowledge if you plan to venture in there looking for fun.