Green’s Dictionary of Slang

jip n.3

(Irish) semen; thus as v. to ejaculate.

[Ire]G. Coughlan Everyday Eng. and Sl. 🌐 Jip (n): sperm.
[Ire]P Howard Braywatch 97: ‘Carolyn Ansboro pulled me off one night in her old dear’s Opel Vectra [...] I jipped all over her old dear’s seat covers’.