I have been tried Cannabis milk several times, when I was much younger. Its very very strong high, and long lasting, even too long lasting. The high was very smooth, without any fluctuations, and I felt myself as if I'm in a corridor without an exit.
In the thread are 2 opinions, written above, by a mate from South Africa and another man, I guess the opinions are important, I repeat its here:
1. The milk could be cooked from any weed, any hemp you can find.
2. Do not use any butter, its too harmful for the digestion. Milk cream, that is the best.
3. My personal recomendation - don't drink the milk when you are alone, the drink is a company one.