It derives from a World War I term for bunk mate or close friend.

One of Ken's bunk mates and a nerd stereotype.

Although I imagine that most women don't want to hear what happens between her potential mate and his old bunk mate in prison/school.

We could always argue about who got the vamps as bunk mates after I saw Richard.

Accommodations range from cabins in the woods with bunk mates to luxurious inns.

First night, his bunk mate had curled up in the corner and begged him not to rape him.

I turned back to my two bunk mates.

But no sign of my two bunk mates.

But he insisted he didn't know anything about my two bunk mates.

Additionally, Carl would regularly wake up in the middle of the night and pee all over his bunk mate.