Threesome

A threesome is three people in a collective romantic relationship or simply all in bed together. This may be any combination of sexes; three guys, three girls, two guys and a girl, two girls and a guy.

In 3.01 The Magnificent Seven, Dean may have been in a threesome in the opening scene.

In the Supernatural fandom, this is most frequently expressed as Sam, Dean and another character. John/Dean/Sam is the most common, but Sam/Jess/Dean and Dean/Jo/Sam are also found, as well as threesomes featuring both male and female original characters. Not all threesomes feature the leads though; for example, John/Bill/Ellen has occurred in fanfiction.