fart sack

He lay in bed for a moment, dreading the cold, then rolled out of the fart sack.

Military slang, in any language, is also full of humorous expressions; the term "fart sack" is military slang for a bed or sleeping bag.

All that done he changed into a set of sweats and socks, slid his .45 under the pillow, slipped into the fart sack and drifted off to sleep in a haze of chemical protectants.