The third time a person has sex with two people at one time. That is, the third threesome
. Analogous to golden birthday
Any kind of threesome counts. Three girls, three guys, two girls and a guy, or two guys and a girl.
First, Dick slept with Jane and Sally. Then Dick slept with Jane and Tommy. Then, for his golden threesome
, Dick slept with Angela and Tammy, successfully completing his golden threesome.
It may be many years before Dick pulls off a golden foursome.