Odonata: Coenagrionidae
Austroagrion watsoni
Male damselflies (and dragonflies), unlike any other insects, are endowed with two sets of genitalia. Before mating can occur, the male must transfer sperm from his primary genitalia (near the end of his abdomen) to his secondary genitalia (near the front of his abdomen). Typically damselflies make the transfer soon after they are in tandem (and true dragonflies do it before they grab a female).*
Here, the male Eastern Billabongfly whilst holding his female in tandem, is in the process of transferring sperm from his primary genitalia to his secondary genitalia.
The male is hosting a number of parasitic red water mites attached to the underside of his thorax.
*Chandler, David and Cham, Steve (2013). Dragonfly. New Holland Publishers, p.90.