Green’s Dictionary of Slang

lickety-split adv.

also helitywhoop, lickerty-clip, licketty-cut, -split, lickety brindle, -click, -cut, -spit, -splickety, -switch, lickity-cut, -split, lick-to-split, linkerty-clink
[most alternative forms faded by late 19C]

[mid-19C+] (orig. US) fast, with some onomat. overtones.

In phrases

go lickety-split (v.) [pun on split n. (3a)]

[1990s+] to give oral sex to a woman.