I take it you are referring to marry jane, on the grounds that tobacco is legal.
So I have a question for you: Why is it that the longer somebody does drugs the more they feel the need to 'identify' themselves as a drug user as a social group?
I get a bit fed up with long time drug users wearing their addiction on the outside as a badge of pride.
I'm an ex-junkie myself, and i'll put my hands up and admit that there is none so righteous as the converted. The last thing I ever wanted to see is references to drugs all over the place. Even in LFS there are people with drug related user names and drugs blazooned all over their car skins, often with supposedly amusing slogans.
It's the same with alchohol too, although I still abuse that on ocassion, some people feel the need to boast about how much they are screwing themselves up with the stuff.
My advise: Try it, understand it, walk away.