To copulate, to beat. If she wont wap for a winne, let her trine for a make; if she won’t lie with a man for a penny, let her hang for a halfpenny. Mort wap-apace; a woman of experience, or very expert at the sport.
Definition taken from The 1811 Dictionary of the Vulgar Tongue, originally by Francis Grose.
Wall * Wapper-eyedNathan Bailey's 1736 Dictionary of canting and thieving slang
John S. Farmer's collection of canting songs and slang rhymes