Feague

FEAGUE, to feague a horse; to put ginger up a horse's fundament, to make him lively, and carry his tail well; it is said, a forfeit is incurred by any horse dealer's servant, who shall show a horse without first feagueing him, used figuratively for encouraging or spiriting one up.

Source: wiktionary

Feague. To feague a horſe; to put ginger up a horſe's fundament, and formerly, as it is ſaid, a live eel, to make him lively, and carry his tail well: it is ſaid, a forfeit is incurred by any horſe dealer's ſervant, who ſhall ſhew a horſe without firſt feaguing him. Feague is uſed, figuratively, for encouraging or ſpiriting one up.

Source: wiktionary

Run along to Hobson's Livery Stable and tell them I want a good fast horse, right? Something with a bit of fizz in its blood! Not some feagued-up old screw, and I know the difference! I want it here in half an hour! Off you go!

Source: wiktionary

“... One of those chaps over there said someone feagues his horse. What the hell’s ‘feague’?” / O’Reilly’s sides heaved. “Feague? You’d know it as a different expression, but it’s a trick unscrupulous horse dealers use to make a horse look better than it is. You can judge a horse’s spirit by the way it carries its tail.” / “That’s what he said.” / “So,” said O’Reilly, “just before the buyer comes to look at the beast, the dealer sticks a clove of ginger up its rectum. Feagues the poor creature.” / The thought made Barry wince.

Source: wiktionary