Sorry to come off like an ass.. but your mom is cool with you smoking in her house, at least live by her rules. Don't smoke fucking cigs. It's as simple as that. She respects you enough to let you smoke weed in her house, something that I wasn't lucky enough to have, and the least you can do is respect her wishes by you not smoking cigs.
Yeah seriously. Very nicely put. I'd say just don't smoke the cigs dude. It would suck if you get caught again and she tells you she doesn't want to you smoking pot anymore either. You're lucky as hell to be able to smoke weed in your house with your mom knowing, so don't fuck it up.