Deco
Australian slang for Dexamphetamine tablets prescribed to people with ADHD but taken for their energetic, confident and euphoric effects. Typically taken in 5mg tablets, either snorted or swallowed. Snorting has a stronger instant effect and lasts around 4 hours, whereas swallowing has a longer come-up and typically lasts 6-8 hours.
"what've you taken tonight?"
"just railed a few decos and had half a bottle of gin hey"