i kept it from my mum for 2 years, its hard work and hell of a lot of lying.
first of all build up a whole anti drugs complex thingy - make sure your mum thinks that your friends smoking upsets you.
then get very very defense if you are accused
use the following excuses but word them well
- im very tired
- i'm drunk
- my friends have been smoking around me (for red eye or the smell)
- i've been crying (mainly girls)
- something flew into my eye (risky)
- hayfever
- its cold out there
- i feel ill
- do i look weird... how odd
do not grab everything from the fridge and then mong on the sofa. Take your time, casually ask if you can have something to eat or say 'i might grab a bite to eat'.
if you feel that all this is failing, avoid all eye contact and head straight to bedroom.
Above all else do not let your parents drag you into a long conversation... it will not go well