A drug made back in the eighties in a garage lab that gave you the best high of your life. The substances in the drug happened to be lethal and hence the reason you got the best high of your life-because you died afterwards.
I'd say White China is almost kind of like when you decide to lock yourself in the bathroom with bleach and ammonia. (Yeah I know a few people who've ignorantly done it). Very light-headed, and very airheaded because you are dying from fumes.