I can see you starting to twitch and strain already. I've barely begun testing you and already you can hardly contain yourself. How sad. It's only going to get more difficult you know.
Grip the base of your cock and with the fingers from your other hand start making light concentric circles around your balls. Squeeze your cock as hard as you can while you play with your balls and count slowly to 50.
Now loosen the grip on your cock but don't stop playing with your balls and count slowly to 10.
Do this three times.