If I remember
correctly the drinks they had
in Clockwork Orange were:

Vellocet (meth)
Synthamesc (mescaline)
Drencrom, a.k.a. "knives" (adrenochrome)

Yes, I know that book well.

Mescaline is hard to find these days.
Good luck finding adrenochrome!
and meth.... meh, really who would want to?!
Personally I think a little bit of LSD or shrooms in the coffee ice cream would be awesome. Vhs probably won't do acid, but I bet he'd do shrooms.

Enjoy!