Theres a dogging scene at East Hills (deepwater boat club) but it is very male focused. Went fishing there once, and was asked to go join in. Not my scene, sorry to say. But i do know, there are plenty of spots to start one up.
i took my missus dogging the other weekend... saturday night at Bilgola Beach... gave me head while guys felt her up, then I ****ed in the back before a girl with her man turned up and licked my cum out of my missus, we ended up back at the couples house for some more ****ing.
there are locations for dogging in Sydney, you just have to pay attention, plus there is lots and lots of **** available, not much pussy to play swaps with.
If you are in Sydney have seen some dogging over in coogee on that winding stretch of road near the park next to the sea. The dogging scene is around, just hidden like a ninja.