What the Fuck Are Bosom Buddies?

Bosom is a collective singular noun referring to women's breast area. So what the fuck are bosom buddies? What does that mean? Does it mean like they've had sort of some kind of sexual situation with the same woman? That's my sick mind at work. You can subscribe for absolutely nothing by putting your email in there. And when I post some sinillating fascinating, incredibly informative rant like this, you'll be informed with an email.