Naked bed

a bed the occupant of which is naked, no night linen being worn in ancient times.

See also: Naked

Webster's Revised Unabridged Dictionary, published 1913 by G. & C. Merriam Co.
References in classic literature ?
In the centre of the current there was an extensive and naked bed of sand, but a little raised above the level of the stream and of a colour and consistency which warranted, to a practised eye, that it afforded a firm and safe foundation for the foot.
Then comes, in each room, one of Kounellis's signature gestures: the home furniture found in a local flea market, for example the naked bed frame and the Thonet chairs, or the walled-in doorway filled with slightly smaller stones.