Green’s Dictionary of Slang

(UK black) to kiss passionately; also n, a kiss.

2005		Jade LB Keisha the Sket (2021) 24: we sat der lipsin.
2007		Skins ser.1 ep.3 [TV script] ‘I’d like a lips from Michelle.’ [...] ‘He wants a kiss’.
2017		theculturetrip.com ‘Guide to London Slang 10 Jan. 🌐 Lips – to kiss passionately after a night out.
2020		G. Krauze What They Was 43: Once I pinned her down we’d start lipsing.