[Serious] Best Pee Strat

Sorry if this is the wrong place to post this, but I need some advice. Tomorrow at 16:00 I need to pee into a cup at the doctor’s office for a drug test and I am a very shy pee-er. Should I hold my morning pee from 8:00 to 16:00 to make sure I have enough of it or should I pee as soon as I wake up and drink water throughout...