It doesn't smell nearly as bad as smoking, but to me smells half like cooking peanut butter and half like cooking weed, but not that strong since it's wrapped in foil. If you're worried about smell, just cook something else in the microwave at the same time that smells pretty strong, or air freshner, there are many options. But no it's not going to smell your entire house up or kitchen at all. the first time we made them my mom came over about an hour later and didn't even mention anything about smell. I'm not sure about how long u can leave them sitting. I just made sure and ate them as soon as they were cool enough to eat right out of the oven. I also used natural peanut butter, the one that's not partially hdryogenated, but I don't think it really matters. Anyway be creative with the smell, I doubt you'll have any problems at all with it.