hmmm, trying to figure out my drug etiquette that hasn't been already mentioned . . .
well for one, if you're inviting people to go to an event or club or something, and you're getting pills/whatever, make sure to offer to get for whoever is coming. I hate it when people invite me to go somewhere and then I show up and everyone is high and they never offered to get me some.
also, when someone invites you to go to an event where you will be rolling, don't bring your stupid drunk/sober friends who are gonna annoy the rest of your group that's rolling. ask before bringing others into the group.
above all, this pisses me off the most. "Wow man, this weekend, I got some amazing (insert drug that you've been looking for for a long time but never managed to get ahold of/are in short supply of) dude it was great" Cool, did you get me any? "Nope"