Green’s Dictionary of Slang

(Aus.) kissing.

1964		D. Cusack Black Lightning 51: A System of Numbers (One to Fourteen) gives you the clew to the amount of pashing a vergin or near vergin permits and expects.
1988		‘Kylie Mole’ (Maryanne Fahey) My Diary 99: Pashing is somethink you shood only do wif your own boyfriend.
1996		Capital Q Weekly (Sydney) 29 Mar. 34/1: People are often left with love bites on these after a heavy session of pashing.