Green’s Dictionary of Slang

kiss my arse! excl.

also kiss mine! ...my ass! ...my assorted peanuts! ...my Aunt Annie’s preserves! ...my axle! ...my backside! ...my bender! ...my blackass! ...my breech! ...my butt! ...my cuff! ...my royal hindparts! ...my Royal Irish! ...the seat of my pants! ...where I did sit on Sunday!
[arse n./ass n. note Chaucer, Miller’sTale (1386): ‘But with his mouth he kiste hir naked ers’]

1. [early 16C+] a general statement of contempt or dismissal; often ext. as kiss my ass in Macey’s window!

2. [1970s] (US) an excl. of surprise.

In exclamations

I’ll be a kiss my ass!

[1950s] a general excl. of surprise, amazement, delight, etc.