(n) is when 2 individuals lite up a doobster and each fellow takes a hit and holds their smoke in until the other person passes the doob back.
Larry rolls up a joint and asks Tim if he wants to blaze. Tim says "Lets have a Weedercise!" Larry Sparks his spliff and inhales his smoke then passing the joint to Tim. Tim takes his hit and holds it in too. Once Tim gives Larry the doob back Larry exhales his hit and takes another one. They continue to pass it back and forth holding in their hits untill they get the joint back. Once they've finished they watch sum toons.