In 19th century slang, a BUFF-BALL was a dance party at which everyone was naked.

(Slang and Its Analogues Past and Present, 1890) pic.twitter.com/zRTS0EKNL4

— Haggard Hawks (@HaggardHawks) March 27, 2018

Naked Victorian Dancing, in Which Much Fun Was Had by All https://t.co/bMeoaY6sWV

— Sarah Jamila Stevenson (@aquafortis) March 28, 2018