Green’s Dictionary of Slang

feather-bed n.

1. a boxing-glove.

[UK]F. Swainson Acton’s Feud [ebook] ‘Brought the mittens with you, too?’ ‘Yaas, sir, I have the feather beds’.
also feather-bed and pillows
[resemblance]

2. (US) an extremely fat person; also attrib.

[UK]J. Diprose London Life 45: Oh, isn’t she von for cramming herself; blessed if she ain’t a regular feather bed vot’ll always hold more.
[UK]Farmer & Henley Sl. and Its Analogues II 380/1: Feather-bed and Pillows, subs. phr. (venery) – A fat woman.
[US]Nicholson & Robinson Sailor Beware! I i: wop: Too skinny. mattie: You polacks all go for them feather-bed mamas.
[US]WELS [DARE].

SE in slang uses

In compounds