etymology - Was “tickle (someone's) fancy” originally a double entendre?

Recently, I asked users to provide modern-day equivalents of idioms and expressions that contained the words fancy and tickle. The question is titled Whatever tickles their fancy in the US?

I was pretty much convinced that the idiom was quintessentially British, and that few American speakers had heard of it, let alone used it in their everyday conversation. According to Google Books Ngram, I was very much mistaken, since the 1970s the idiom has become increasingly popular in the US (blue line) whilst the opposite is true in the UK.

Now for the fun part. Looking into its origin, I discovered that the idiom tickles your fancy (which basically means “what pleases you”) was originally (?) a double entendre. The term fancy was a euphemism for fanny which in BrEng is a vulgar expression for female genitals but in AmEng is another name for butt or buttocks.

In A Dictionary of Sexual Language and Imagery in Shakespearean and Stuart Literature By Gordon Williams, under the entry of fancy, it says

fancy It means vagina, with a pun on the sense of sexual desire (cf. the current ‘a little of what you fancy does you good’), in Thornley's Longus (1657) p.124, when Daphni's seductress ‘directed him to her Fancie, the place so long desired and sought’.

Under the entry of tickle, page 1389, it tells us

Merry-Thought (1731) I.27 records an ephemeral couplet of 1714: ‘Dear Doll is a Prude, And I tumbled her down; And I tickled her Fancy For half a Crown’. This quibbling phrase turns up in Maids Complaint (1684-6; Pepys Ballads IV.50), the maid enviously hearing “my dame Nancy declare how her Master did tickle her fancy With his dill doul; and in Unconstant Quaker (c.1690; Pepys Ballads V.241), where the Quaker maid was ‘left in the Lurch, after he had Tickl'd her Fancy’.

Unfortunately pages 1387 to 1388 are not available for viewing, so I have no way of knowing if the variant ‘Whatever takes your fancy’ was ever used in 17th or 18th century England.

Questions

1. Was “tickle [one's] fancy” originally a double entendre expression?


2. Where and when was it first used?


3. Did Americans use this idiom as an innuendo? Are there any examples from 18th or mid-19th century American literature (i.e. 1700-1850) that support this? Instances of tickle [your] fancy will also count.


4. Is there a term for an expression that used to be a double entendre but is now regarded as being "normal"?