Green’s Dictionary of Slang

1. (US) to have sexual intercourse.

[1597		T. Deloney Pleasant Hist. of Jacke Newberie (1633) xi M: Sir George having received this answer was wonerous woe, cursing the day that ever he medled with Joane, whose time of deliverance would comme long before a twelve Moneth were expired to his utter shame].
[1612		N. Field Woman is a Weathercock II i: wag.: I am with child by you. pen.: By me? Why, by me? A good jest [...] Why, do you think I am such an ass to believe nobody has meddled with you but I?].
1942		in G. Legman Limerick (1953) 131: A hermit who lived on St. Roque / Had a lily perfected to poke. / He diddled the donkeys / And meddled with monkeys.
1975		G. Underwood ‘Razorback Sl.’ in AS L:1/2 62: meddle vt [...] 2: Have sexual intercourse with.

2. (US black) to be intimate, but not spec. on a sexual level.

1975

G. Underwood ‘Razorback Sl.’ in AS L:1/2 62: meddle vt [...] 3: Be intimate with (someone) but not necessarily through sexual intercourse (black use).