Dear Jackie: one definition of "squab" is a cushion:
See Def.#3 below:
Webster's 1913 Dictionary

Definition: \Squab\, a. [Cf. dial. Sw. sqvabb a soft and fat body,
sqvabba a fat woman, Icel. kvap jelly, jellylike things, and
and E. quab.]
1. Fat; thick; plump; bulky.

Nor the squab daughter nor the wife were nice.
--Betterton.

2. Unfledged; unfeathered; as, a squab pigeon. --King.


\Squab\, n.
1. (Zo["o]l.) A neatling of a pigeon or other similar bird,
esp. when very fat and not fully fledged.

2. A person of a short, fat figure.

Gorgonious sits abdominous and wan, Like a fat squab
upon a Chinese fan. --Cowper.

3. A thickly stuffed cushion; especially, one used for the
seat of a sofa, couch, or chair; also, a sofa.

Punching the squab of chairs and sofas. --Dickens.

On her large squab you find her spread. --Pope.


\Squab\, adv. [Cf. dial. Sw. squapp, a word imitative of a
splash, and E. squab fat, unfledged.]
With a heavy fall; plump. [Vulgar]

The eagle took the tortoise up into the air, and
dropped him down, squab, upon a rock. --L'Estrange.


\Squab\, v. i.
To fall plump; to strike at one dash, or with a heavy stroke.
[Obs.]