I mix my weed with tobacco, have done for years whether I am smoking a spliff, pipe or a bong. I am from Australia where (in Melbourne atleast) mixing weed with tobacco is just the done thing, when I started smoking I actually resisted this idea and would typically only smoke straight green. As time went on and I would smoke with other people more often, I was consequentially forced to start smoking a mix every now and then, being a fairly broke stoner in High School I couldn't help notice that a little bit of tobacco does tend to make a stash go just a little bit further and so I adopted the practise.
I think there are a number of benefits to adding tobacco, for one it does spin out the stash a little further, it also makes the smoke smoother to inhale (this only applies if you are used to tobacco smoke obviously) and the nicotine buzz I find is a pleasant filler for the few minutes it takes for the weed to kick in properly. It also makes the weed burn a bit better, honestly if you are using a pipe or a bong then it doesn't make THAT much difference and you would have to be smoking wet shit to really need to add a cig to be able to punch a cone easily, but imho if you are rolling a spliff then it is plain wasteful not to add a bit of tobacco.
All that said, there are quite a few negatives associated with it. For starters, it is clearly a lot worse for your lungs to be smoking tobacco with your weed, tobacco is probably more harmful to the lungs than weed is and regardless of your opinion on that smoking both together is going to be worse than smoking either one on its own. It has a negative influence on taste, except in a joint, but particularly through a bong it can be pretty manky. I also believe that smoking a mix makes the practise of smoking cannabis notably more addictive, as you get addicted to the nicotine and associate the consumption of nicotine with the consumption of cannabis which reinforces your desire to habitually use cannabis. I find this to be particularly true when smoking a mix through bongs, as the headrush you get from tobacco in a bong can't really be replicated by just having a cigarette. I actually purchased an American style glass 'spoon' type pipe to try and reduce the amount of cannabis I smoke with tobacco, it is very pleasant to use but in the month I have had it I have honestly only bothered a handful of times... There is just something satisfying about smoking a mix that smoking straight green doesn't really fully satisfy my craving. It sucks and I hope to get away from it one day but for now I am stuck mixing with tobacco.
I would say on the whole that the negatives of smoking with tobacco outweigh the positives (unless you are talking about skinning up, I really feel the use of atleast a little tobacco is pretty much mandatory in this case), and there are probably a lot of current nicotine addicts who never would of become such if it weren't for the fact that habitual cannabis use during their broke, teenage years wasn't made more feasible/cheap by the addition of tobacco.
). I don't know if that counts because it wasn't me mixing flowers with tobbacco, but it's similiar I guess.
