Three Dolphins (Score 1)

According to G Harry Stine's book "Halfway to Anywhere," getting it on properly in space requires a third person to keep the main event from flying apart. This is derived from how dolphins do it. Therefore, the club for those who have done the deed in zero-g is the three-dolphin club. Apparently there is even a patch (helpfully reproduced in the book), and there are allegedly quite a few astronauts qualified to wear it.