Green’s Dictionary of Slang

long-tailed adj.

of a coat, having a long tail.

[UK]C.M. Westmacott Eng. Spy II 170: We must start that long-tailed gib of yours for a nice little square mizen, just enough to cover your beam.
[Aus]J.P. Townsend Rambles in New South Wales 168: The phrase ‘long-tailed’ is an allusion to the emigrant’s carefully-kept church-going coat.
[US]‘Mark Twain’ Innocents at Home 345: A stranger with a long-tailed coat came in.