Green’s Dictionary of Slang

(US/Aus.) to flirt, to indulge in heavy petting or even intercourse.

1929		S.J. Perelman in Marschall That Old Gang o’ Mine (1984) 79: Good old Katerina Ivanovna, with her long prying nose, always wanting to know [...] who you’re pashing on the porch.
1979		Lette & Carey Puberty Blues 104: Wayne pashed me off and I got out of the car.
1983		K. Cue Crooks, Chooks and Bloody Ratbags (1988) 71: For entertainment, they packed the back seats of the Shire Hall each Saturday night to watch the flicks and ‘pash on’ as soon as the lights went out.
1996		Sydney Star Observer 9 Feb. 28/1: For the record, Harriet’s seduction was unsuccessful, and she then went and pashed Noel Ferrier, leaving her chewing gum in his mouth.
2003		McGill Reed Dict. of N.Z. Sl. 153: pash on/pash up Vigorous kissing and cuddling.
2004		L. Redhead Peepshow [ebook] Getting so pissed I ended up pashing some grungy rocker.
2014		me-stepmums-too-fuckin-hot-mate at www.fakku.net 🌐 You’re pretty cute [...] so I kinda went an’ full-on pashed you.
2023		J. Turner in LRB 5 Jan. 🌐 Renaud, the much older ‘cousin-uncle’ whom Claudine pashes on, then marries.