drug testing problem

[d- mise]

hey guys i got a pretty serious question for anyone on this post that has an experience or knowledge about a topic. I have recently at my college heard we will be having random drug testing. I have been taking anavar(10mg tabs) and 7 cc of winny over the past three weeks. If i am picked i plan on trying to switch my urine. I plan to do this with catheder i have a nurse to do the procedure but i have a question, how do u get the "clean " urine back into the empty bladder. I know that this is a touchy subject but i have no choice i just some some info but i dont have a lot of time. Oh yeah the ncaa is doin the test so any info on that would be cool to. thanx guys