The following gems come from my experience growing up in Melbourne's south east suburbs during the late 80s and early 90s. It's 1989 when the narrator of With the Music is 14, so she would have used these expressions to death. Please share your own memories in the comments.
Aggro: to be in a bad mood. Dad was real aggro that Yola got suspended for smoking.
Bag: to talk disrespectfully about a person. Kathleen told me to stop bagging Bert Newton because he's actually a very witty and informative man.
Bible basher: religious people. Some of the boys at Julia's youth group are spunks, but they're all bible bashers.
Bulk ace: something that's really good. Last night's episode of Neighbours was bulk ace.
Bush pig: an uncultured person, resident of the outer suburbs or country Victoria. Lucy has become such a bush pig since she moved to Ringwood.
Cube: a boring person, usually an adult who is so square they resemble six squares stuck together. Mum is such a cube, she won't buy me any Island Coolers.
Dero: short for derelict, someone who's rough. State school boys are such deros.
Drop: to break up with someone. Courtney dropped Con because he didn't have his own car.
Dud root: someone who's bad in bed. Melanie was never sleeping with Todd again; he was such a dud root.
Feral: disgusting and/or unpleasant. Tricia is so feral; she doesn't use Impulse and she listens to Simply Red.
Full on: extreme. Jimmy is a full on bogan; he lives in Laverton and goes to a state school.
Fully sick c*nt: a young male who is considered cool, but a trifle flashy and overly fond of cars. Jason is a fully sick c*nt; he has his drivers licence.
Get with / get on with (past tense is "got"): to kiss someone. I think it was around 1988 when "pash" was replaced by "get with" and you were a pariah if you still used the word "pash". Marilyn got with three boys at the blue light disco.
Go with: to date someone, be it for a day, a week or even longer. Charlene is going with Scott.
Hanger: a boring kid who follows you around, they were leechlike and "hung off" a group of popular kids. Simone hangs off us all the time and she never has any good stories about boys.
Klepto: short for kleptomaniac, someone who steals things, can also be used as a verb. Tiffany kelptoed my Bros pencil case.
Mole: a girl who was considered a bitch, the plural being mole patrol. Becky didn't want to go to the blue light disco because she hated running into that mole patrol from the Catholic school.
Palm: to break up with someone. Tara was turning into a clingy mole, so Will palmed her.
Rack off: expression used to tell someone to go away. Rack off, Stacey, you're such a hanger!
Rage: used as a noun or a verb, to party. The after party was a real rage. We raged all night at the after party.
Schitz out: to unexpectedly lose your temper. Mum schitzed out because I got orange Twistie crumbs all over my blazer.
Scrag fight: a physical fight between two girls. Bianca and Marilyn got into a scrag fight after Bianca got with Marilyn's boyfriend.
Skeg: a cool boy into surfing or skate boarding, normally dressed in fluoro board shorts. Angus is such a skeg; I love him sooo much!
Skinner: a younger kid, named so because of their lack of pubes (people had pubes in the 80s). Abbie is going with that little skinner in Year Seven.
So excellent: very good. It was so excellent that Tara got detention cos she's a real mole.
Spewing: feeling disappointed. Gita was spewing she didn't get tickets to the Boom Crash Opera concert.
Splendo: posh, probably owns a yacht. The boys at Scotch College are such splendos.
Spunk: a handsome male. George Michael is such a spunk!
Sux: sucks. School sux.
Tight arse: a person who places restrictions on your fun, or doesn't give you money. Dad is such a tight arse; he said I have to get up before eleven am even on the weekend. I need $50 to buy some clothes from Cherry Lane but my tight arse parents won't give it to me.
Try hard: an unpopular kid who tries too hard to impress. Look at Kim in those try hard fake Converse from K-Mart.