You'll piss in a cup and then they'll dip a test strip in the urine for 15 seconds,wait about 5 minutes and it'll show positive or negative.You could try drinking alot of fluids,you're parents aren't going to know whether its dilluted or not.But as much as you've been smoking it doesn't look to promising.I would be tempted in going the quickfix route.Not sure if the bleach in the urine would help.The home test kit isn't going to test for an adulterated sample.