I almost never cough, the only situation in wich I cough, wich happened somewhere last week for the last time, is when I have a sore troath(still have, last signs of the cold I had, partying and going to a festival didn't really help in curing my throat) and on top of that I load my vaporizer(underdog) with mostly kief.
when I just started smoking, and mostly smoked joints(without tobacco) I learned myself not to cough since coughing only made it hurt more, and since then I almost never cough, smoke or vapor. the only time I coughed without having a sore troath, was when a friend handed me a cigaret saying there was weed in it(there wasn't), tobacco makes me cough much easier and since it was unexpected even more so.