Halitosis

A scientist has a wife who suffers from terribly bad breath. They get invited out for a meal with a local bigwig, but the wife doesn't want to go on account of her problem. The scientist invents a really bright lipstick for her that will nullify the smell as she breathes out, the only problem being that it is difficult to apply, as it breaks rather easily if too much pressure is applied.

The moral of the story? Supercolouredfragilelipstickexpelshalitosis.