I'm picturing energetic and socially conscious "hip" 20-somethings doing a country-wide elementary school tour where the whole school gathers in an auditorium to watch them rap about the dangers of social media.
Thinking about myself and what I remember. What worked for cigarettes was, graphic demonstrations of health issues along with lots of real proof. The government and society made it inconvenient to use it everywhere.
I don't they held back, I remember getting shown rotting lungs, the effects of lung cancer, holes in the throat, yellow teeth. Lots of death statistics.
If it works for cigarettes...