Need to p a drug test for probation?

Ok my po called me today saying be in the office at 3pm for a drug test i've smoked about 7 js this month i say less than 7-9 grams of trees i went and bout a drink called the stuff and some cranberr juice its now 4pm should i p i need to p? Is the any other way for a sure p? Anyone ever used this drink and ped? What are the exact steps to this drink so ill know im doing it right? Please keep your negative comments to yourself i dont need them thanks...