Green’s Dictionary of Slang

tickle your fancy n.

[rhy. sl. = nancy n. (2a)]

a homosexual.

[US]Maledicta II:1+2 (Summer/Winter) 119: Elsewhere Aylwin lists a few more ‘Vulgarities’: [...] nancy (tickle your fancy, a homo).
[UK]B. Kirkpatrick Wicked Cockney Rhy. Sl.