ooo boy....
Well, I guess I'll start with weed, even though it isn't my drug of choice anymore (though not by my choice...damn UA's)
I knew quite a few of my brother's friends smoked, and one time I was staying up with two of them (who actually happened to be my age). We were up all night watching movies at one of their house's, and in the morning, I said something like "You know, I want to smoke weed" so we went to the other kid's house and I smoked. I could also get into the first kid I knew that smoked (also a friend of my brother) or finding my dad's pipe when i was like 15, but those weren't true "introductions"
(ironic that my brother knew all the potheads, but he started smoking years after I did)
The first time I did shrooms, I was hanging out with another buddy and we couldn't get any weed. I thought I knew someone who had some, and when we called him, he told us to come over. However when we got there, he said he couldn't get any. But he could get us shrooms. We bought an eighth (supposedly) and he came back with one giant shroom. we split it and didn't really get that high. Didn't get real good shrooms till several years later, after doing a bunch of 2c-i.
Alcohol and cigarettes are probably my current drugs of choice, but only due to availability and ease of use (ie i can drink every day, unlike shrooms). I started smoking because it was something to do when we couldn't get weed. The Walgreens near my buddys house had the cigarettes behind the counter, but for some reason they kept the cigars and pipe tobacco in an aisle. We'd steal either a pack of Swisher Sweet Cigarillos (i think that's what they were called, been about six years since I smoked them....they were basically cigarettes with cigar tobacco, had filters and all) or some pipe tobacco, since most gas stations would sell papers without an ID. I didn't get drunk till I got to college, like second week, in this guy's dorm room. Three keystone lite's and 2-3 shots of Jaeger and I was toasted....o to be a lightweight again.
