Green’s Dictionary of Slang

(Aus./N.Z.) to caress the buttocks; to ‘goose’, i.e to stick a thumb or finger into someone’s anus.

1972		D. Hewett Bon-bons and Roses (1976) 52: ‘I was up on a chair fixing the new curtains and he comes up behind, and dates me. Large as life. Without a word of a lie. He dates me. Cheeky mug’ [Simes:DLSS].
1976		D. Ireland Glass Canoe (1982) 13: Just as he reached the vinegar stroke, Mick dated him.
1982		P. Radley My Blue-Checker Corker 108: Duck was now perched on Kyle’s fence and dating her up.
1985		R.G. Barrett You Wouldn’t Be Dead for Quids (1989) 145: Norton [...] dated the snooty receptionist on the door; she screamed.