Green’s Dictionary of Slang

1. to make things happen, to intensify things, to spice things up.

1928		R. Fisher Walls Of Jericho 306: turn ’em on Strut one’s stuff.
1944		L. Glassop We Were the Rats viii: You ought to see the Jerries turn it on. [...] They come straight down through the harbour barrage. You wouldn’t think they’d live through it.
1957		Laurents & Sondheim West Side Story I viii: They’re gonna get it tonight; / The more they turn it on, the harder they’ll fall!
1965		W. Dick Bunch of Ratbags 139: We [...] watched Ricky and the boys turn it on, and we asked a couple of dolls for a dance.
2006		B. Matthews Intractable [ebook] If the Parramatta screws wanted to turn it on I would be ready for them.
2012		S. Blass Pirate for Life 128: After slumping a bit during the dog days of August, we turned it back on again and on September 24 hit our high-water mark for the season.

2. (Aus.) to start a fight.

1959		D. Niland Big Smoke 205: Scare him. Might work. Get rough. Might work. Maybe he turns it on; a big blue starts and he gets hurt.
2006		B. Matthews Intractable [ebook] Steve Dowd was the first guy to crack [...] and turned it on with the screws.

3. (Aus.) to provide food and drink, to host a party.

1941		Baker Popular Dict. Aus. Sl.
1957		‘Nino Culotta’ They’re a Weird Mob (1958) 136: Tucker’s on us. [...] You bin turnin’ ut on long enough.
1959		D. Niland Big Smoke 122: That’s why tonight we’re going to turn it on. You see, Young Frosty’s a pal of mine, and me and the mob are going to help him celebrate the big event.
1988		McGill Dict. of Kiwi Sl. 115/2: turn it on give a party or buy drinks.
2003		McGill Reed Dict. of N.Z. Sl. [as cit. 1988].

4. (Aus.) to allow or offer sex, often with more than one partner.

c.1943		S.J. Baker Aus. Vulgarisms [t/s] 14: turn it on: (Of a woman) To accept the amorous approaches of a male.
1944		L. Glassop We Were the Rats 147: She was pretty grateful, ya see, an’ well — well she offered ter turn it on.
1963		(con. 1944) L. Glassop Rats in New Guinea 87: ‘What’s a nympho?’ [...] ‘A girl who turns it on for the boys.’.
1973		(con. 1940s–60s) Hogbotel & ffuckes ‘Pull me Dungarees Down’ in Snatches and Lays 55: Well, when I turn it on, Don, / I really turn it on; / Come away from Ron, Don! / ‘’Cos now I’m turning it on.
2005		M.B. ‘Chopper’ Read Chopper 4 5: Piss Ant had to provide a stripper to put on a show and turn it on for the boys.

5. (N.Z. prison) to inject a narcotic.

2001

D. Looser Boobslang [U. Canterbury D.Phil. thesis] 194/2: turn it on v. to take an injection of heroin or other intravenous drug.