Amusing question, although I do not advocate the use of illegal or dangerous substances. "To get stoned" or "to be stoned" means to be under the influence of drugs. This phrase usually refers specifically to marijuana, although occasionally it is used to describe other druges. To be under the influence of alcohol is "to be drunk". The phrase "to be high" can also be used. Someone else claimed that this phrase might have at one point been used to literally be pelted with stones. Personally I have never heard this phrase used to convey this meaning. This might be due to our age difference. He is in his 60's and I am 31. Nowadays I the phrase is almost univerally, in my experience, mean to be under the influence or drugs.