Milk laced with a drug. In the book, A Clockwork Orange, milkbars would sell milk instead of alcohol so that they could serve minors. The milk would be laced with "designer drugs." Note that in real life milk is not a very effective delivery system for most psychoactive drugs.
The Korova milkbar sold milk-plus, milk plus vellocet or synthemesc or drencrom. Moloko Vellocet is what we were drinking. This would sharpen you up and make you ready for a bit of the old ultra-violence.
Moloko Vellocet is combination of words that comprise a beverage in European countries. Moloko means "milk" in Nadsat and Russian languages. Vellocet is a slang term for what ever type of amphetamine is available to be added to the milk at the time. This could be any number of amphetamines but LSD and PCP are most common. If ordered today in many underground clubs, Moloko Vellocet in short means "Drug Milk".
I went to the bartender and ordered Moloko Vellocet. He knew what I meant.