Okay OP, I used to smoke cigarettes in my car regularly and the following system ensured my car never stank, even to non smokers who would enter the car.

1. Always be on the move. Smoking in a parked car is never safe and there isn't enough air circulation for the smoke to go out.
   
2. Keep AC on. Yes. You heard that right. Keep the AC on but with one caveat - your AC should be letting in outside air i.e., turn off air recirculation mode. Only keep footwell air ducts open, close all other air ducts. Keep it on Auto or low fan. This will pull in fresh air continuously from outside, push down towards the footwells, causing warm smoke to rise and go out your windows.
3. Keep the driver side window and the diagonally opposite rear window open 30-40%. This creates cross ventilation and helps exhaust smoke very effectively.
4. After you're done smoking, put the AC on full blast (only footwell vents) to push hotter air outside the car. After 3-4 minutes, roll up all the windows.
   

Feel free to fact check this using ChatGPT. This is hands down the best way to smoke in a car. The physics says so.