The stink/The stank

[Jonathon Green]

c.1879–1935 in G. Legman _The Limerick_ (1953) 112: There was a young
curate of Eltham / Who wouldn’t fuck girls, but he felt ’em. / In lanes
he would linger / And play at stink-finger [etc.]

Definitely white (white-collared even) and according to Legman probably
extant from the late 19C. Irving Welsh gives the Scots (and again white)
alternative:

2001 Welsh Glue 39: Ah settles her doon oan the couch giein her the
stinky-pinky for a bit, sliding ma hand up that wee kilt and inside her
pants.

[Note to Jon Lighter: be relieved you don't have transcribe, and indeed
translate Mr W.]

Of course we Brits are equally enamoured of 'finger-pie', hence Lennon &
McCartney in 'Penny Lane' (1967): Penny Lane is in my ears and in my
eyes, / A four [sc. four penny-worth] of fish and finger pie / In summer.

Whether the two Fabs were being dead smart (as they might have put it)
and making a sly reference to fish = woman = vagina, I cannot say.

Jonathon Green