disco biscuit
noun
1
a tablet of MDMA, the recreational drug best known as ecstasy. A heavily ironic identity for a fashionable drug; 'disco' as a nightclub for an earlier generation that didn't have ECSTASY and hence, is considered extremely unfashionable, plus 'biscuit' in the conventional sense of 'a basic supply (ship's biscuit) which can sustain life'. In short 'MDMA brings life to clubs' UK, 1996.
2
the recreational drug methaqualone, best known as Quaaludes™, a tablet of methaqualone. From the popularity of the drug in the 1970s disco scene US, 1993