Definition of "pigtail"

One person […] continued constantly to ply him with the very best pig-tail tobacco, which he had most carefully cut in very small pieces purposely for him.

1828, JT Smith, Nollekens and His Times, Century Hutchinson, published 1986, page 265

Such a filthy spectacle as we presented I have never seen before or since, and it will perhaps give some idea of the almost superhuman dignity of Billali's appearance when I say that, coughing, half-drowned, and covered with mud and green slime as he was, with his beautiful beard coming to a dripping point, like a Chinaman's freshly-oiled pig-tail, he still looked venerable and imposing.

1886 October – 1887 January, H[enry] Rider Haggard, She: A History of Adventure, London: Longmans, Green, and Co., published 1887

[I]t was something that every schoolboy of my generation almost `had' to do, as obligatory a proof of impending manliness as scrumping apples or pulling girls' pigtails.

2000, Bill Oddie, Gripping Yarns, page 12