Any really. The best chance to go is when you get to your MOS school is to graduate first in your class and most times the Instructors (Monitor) will let you pick your first duty station as a reward. If you don’t get first in your class, volunteer for orders to Japan or try to trade orders with someone else who did. Other than that you’ll have to get lucky like everybody else in the Marine Corps trying to get orders to Japan.
Most likely your Recruiter is making sure you’re not still par taking of the activity. My suggestion to you is say you never failed a drug test (unless that’s not true) but you have tried it and no longer want it.