quaker, n. — Green’s Dictionary of Slang

quaker n.

[it is long and thin, hard and ‘wears brown’]

a hard, and poss. lengthy, piece of excreta.

1864, 1867, 1870		Hotten Sl. Dict. 208: QUAKER, an unlawful sir reverence.
1997		Roger’s Profanisaurus in Viz 87 Dec. n.p.: quaker n. Stool.

bury a quaker (v.)

to defecate.

1890–1904		Farmer & Henley Sl. and Its Analogues.
1997		Roger’s Profanisaurus in Viz 87 Dec. n.p.: bury a quaker euph. To release a payload from the bomb bay (qv).