^^barely any. plus it cools the smoke
gently roll the cigarette between your fingers. the tobacco will start to loosen, and can be poured out. if you're tearing the paper, you're probably working it too hard. I'm assuming you want to do this as a subtler method of smoking, so save part of the tobacco (see below for why). grind your weed finely, then mix it with the tobacco. repack using...well, i honestly dont remember what i used to use, but be a creative stoner and find something.
Blaze, what kind of cigarettes are you using? i used to make them all the time, and i used Djarum Blacks, because a)the paper is stronger, and b)if anyone smells anything funny, they see a guy smoking a clove and think "oh, thats what that is"