tolerating my students to smoke for good grades

Im a substitute teacher, before i start the class, i saw some of the students smoking secretly , hiding, their parents doesn't know about it, so as a punishment for them, i let them smoke with me, we will do this everytime i saw my students smoking again secretly and hiding to their parents about their smoking addiction, yes im tolerating them, aside of calling this a punishment, yet its entertaining to me. how fun to cover the room with full of smokes from my cigarettes and from their cigarettes, i let the others go since some of my student cant breathe and not smoking, but next time, when teacher tamtam strikes again inside the classroom, i will make sure everyone gonna smoke with me whether you like it or not, smoker or non smoker, brave or coward, stupid or brainy. everyone will follow me once i told them, for a passing grade!