Have you gathered everything? Good.
It really goes without saying (but I´ll say it anyway in case you´re completely daft) that you will not cum without permission!
Should you ever by accident start to cum, I want you to stop stroking immediately, squeeze your balls as hard as you can and let your cum dribble out. You will then immediately lick it all up (without making a fuss about it or even thinking about it!) and slap your face ten times!