Green’s Dictionary of Slang

falling sickness n.

sexual intercourse.

1594		Gesta Grayorum in J. Nichols Progresses and Processions of Queen Elizabeth (1823) III 337: If any woman be trobled with fallinge sicknes, let her not travayle Westwardhoe, because she must avoyde the Isle of Man; and for that it is an evill only outward into her, let her for a charme alwayes have her leggs acrosse when she is not walkinge, and this will healpe her.
1615		T. Overbury New and Choise Characters n.p.: [A Maquerela] Only her beds are most commonly in print: she can easily turne a sempstresse, into a wayting gentlewoman, but her Ward-robe is most infectious, for it brings them to the Falling-sicknes.
1624		Fletcher Wife for a Month I i: There’s no such cure for the she-falling sickness As the powder of a dryed Bawds Skin.
1654		Mercurius Fumigosus 9 26 July–3 Aug. 84: A young Shameshitter [i.e. sempstress] [...] having the falling Sickness comming upon her, slid backward into a Ditch, where by chance, a young man came to comfort her; her Fitt was very strong upon her, but by the young mans help she soon recovered, ever since she wearing green Ribbins at her elbows because that with lying along on her back in the Fitt, she had worn out all her gown and elbows.
1661		G. Rogers Horn Exalted 24: [Parsley] doth cause in men the Falling evil: Coition too is a petty Epilepsy.
1673		Head Canting Academy 158: What’s the best remedy for a woman that’s troubled with the falling sickness? – It may be cured by a spell of the only crossing her Leg.
1705		N. Ward Fortune’s Bounty 10: [Physicians cannot cure] The Falling Evil in their Wives; Who when their Frensies were upon ’em, And on their backs their Fits had thrown ’em, They could not rise ... Whilst any Man was standing by ’em.