When two males acknowledge having been intimate with not one, not two but three different females and remain on good terms with one another, the men are now bonded by having shared the same igloo at one time or another.
Said interactions with three different females need not have occurred at the same time.
See "Eskimo Brother". Also see "It's not gay if it's in a three way" (indirectly related concept).
M1: "Yo dude, I gotta tell you, but I totally hooked up with that chick you boned last year."
M2: "Man, it's fine, because I did it with that other chick YOU hooked up with last year."
M1: "Dude, this would totally be fucked up except we have also both completed our eskimo hattricks by fucking Jen."
M2: "Good point."
Male 1: "Yea man, I got us a hook up at the show tonight, we don't have to pay cover"
Male 2: "Sweet, how'd you score that?"
Male 1: "I'm bush buddy with the door guy, remember that blonde girl from last weekend?"
Both males pause.
Male 2: "Yep, Eskimo Brother sounds way less homo."