Step 1:Now Dan, go careful, it says 'Do not irritate gums by brushing too hard'. OK, now Dan has to 'Prepare the Duplex mouthtray [that's a gumshield to you and me] by placing the Rapid White Gel in each of the upper and lower reservoirs.' Dan seems to have no trouble at all measuring out the recommended dose of one gram.

Step 2: Now Dan has to uncap the Rapid White Accelerator pen and 'confirm the applicator pad is moist by pressing it against a clean surface'. Can you confirm that the tip is moist, Dan? 'Oh yes, that seems most satisfactory,' he smiles, experimenting on the back of his calf. Now he has to press the pen against the surface of his teeth, taking care not to close his mouth or he'll rub it off.

Step 3: It's gumshield on and away we go. Adam, the photographer, and I relish the silence, as during the 5-10 minutes you have to leave the gunk on, Dan is happily unable to utter a word. How's that feeling now Dan? 'Gmmpph!' Roughly translated, that means it's quite comfortable, a slightly sticky but not unpleasant sensation and doesn't taste of anything in particular.

But then all hell breaks loose! Weak with fatigue after yet another heavy night, Dan commits the cardinal sin of falling asleep with the gumshield in his mouth, when the packaging clearly states: 'DO NOT SLEEP WITH TRAY IN YOUR MOUTH'.

Adam and I quickly shake Dan awake forcefully, saving the day.

That was close. Dan manages to stay out of trouble for the remaining five minutes, and then it's time to remove the gumshield. After brushing his teeth gently with water to remove the gel, Dan takes the final step of brushing with the Rapid White Smile Maintenance Whitening Toothpaste. 'Tastes like a cheapie brand to me,' grumbles Dan. There's no pleasing some people, is there?

So is Dan still a dirty boy? Click here to find out: