the way that i do it, and it works extremely well, is i smoke a ciggerette while tokin...and at the end of every hit, i breathe in some tobacco smoke, and that cancels out the pot smell in your lungs, then you breathe out...and keep smokin your ciggerette...and all that they know is that your smoking a cigerette...

or else, if you cannot smoke ANYTHING in yer housr, just take a paper towel tube...and STUFF it full of dryer sheets, those thing for your clothes, yeah...and then slowly exhale your hits thru that, and then your fine