So I used to live with a non smoker who had no issues with me smoking in a designated room in his house but didn’t want the smell to linger throughout the house. We found the best way to do it is to smoke in a closed room (towel under door for extra points) and blow smoke through a fan in the window blowing out to the exterior. Worked like a charm. Basically you’re creating a vacuum which sucks all the smell outside.

I will say though, If you’re trying to be sneaky and hide the smell from someone who also lives in the house, like a landlord or parent, you’re probably not going to be able to fully hide it no matter what you do. They don’t call weed skunk for no reason... At another place I lived as a young dumb stoner, I figured I could get away with it even though my landlord lived upstairs. There were no vents but it still got through the walls. I tried all the methods mentioned here: fan, smoke buddy, homemade sploof, special candles/incense/ozium, carbon filters, etc. I thought they were working but when you smoke you aren’t a good judge of what smells or doesn’t. Thankfully my LL was pretty chill and just told me I had to stop. I mention this experience because I would strongly advise you not to even try if you have something to lose - like eviction or whatever. Not worth it. Vape carts are discreet af though and definitely changed the game for discreet smoking imo.