Pot + Tobacco = Pass a drug test?

[angryteabag]

My 2 friends and SWIM were TOTALLY blazed at school once (They are relatively new smokers and get high easy off a little)

SWIM had 2 joins of pot and 2 tobacco cigs

My other 2 friends just had 2 joints each

(Yeah it was an expensive Friday)

All of a sudden we get caught Red-eyed and taken to the principals office who then gets us all to do a drug test.

My 2 friends were positive and SWIM was negative dispite the fact that he looked and was totally blazed.