Green’s Dictionary of Slang

(US gay) describing one who enjoys anal sex; thus effeminate.

1949		‘Swasarnt Nerf’ et al. Gay Girl’s Guide 11: kai-kai: NYC MBS [Male Bobby-Soxer] term. As an adjective, anally inclined.
1988		(con. 1940s) C. Bram Hold Tight (1990) 73: I may be more ki-ki than some of you trade.