Green’s Dictionary of Slang

the state of erection.

1654		Mercurius Fumigosus 13 23–30 Aug. 122: The Shemshitter I told you of that was a fortnight agoe cured of the falling-sicknesse by the young man that was strong in a fitt of the Standing Ague, have ever since been troubl’d with a timpany, or swelling rheum in her nether parts.
1660		Wandring Whore II 3: They [i.e. whores] cure the Priapismus, Satyriasis, and Standing-Ague infallibly, with an universal medicine, dancing Boob in-jo, stark naked into the bargain.