Man, you really can't eat just one Milk Dud. You have to keep eating. When you eat one or two, you always get that glob of Milk Dud stuck to your teeth. Your tongue, at best, can make it wiggle about, but it still stays latched on to your tooth. You might be able to extract some with your finger, but it's weirdly gross, and you can never get the whole thing.
The solution? Another Milk Dud. It's the only answer to a stuck Dud. You chew up another Milk Dud, it absorbs the Milk Dud globule, and all that remains is the faint taste of gooey chocolaty goodness.
But lo! The Milk Dud you ate purely out of necessity begat another Milk Dud globule, on a separate tooth. So the cycle begins anew. Once in a while, you're able to end the cycle, out of pure luck. Not only will a new Milk Dud clear your mouth of any residual Dud, it, too, will leave the scene without a trace. You share a moment with yourself, a moment of relief and slight accomplishment- you broke the Milk Dud cycle.
What better way to reward yourself, but with a chewy, caramely, chocolaty Milk Dud?!