By myself or with a very good friend. At least someone that I'm cool with. However, the vast majority of the time, I do prefer to smoke by myself, HOWEVER, most of this is because I'm a lonely fuck who doesn't have a ton of friends to smoke with - bit of a cause/effect kind of thing. If I had a posse or some shit, I'd always be smoking with 'friends'...
If I don't know them, I won't smoke with them 9 times out of ten. Fuck that, instead of "don't talk to strangers" it should be "don't smoke with strangers/people you don't know"...