Allow musical comedian Vikki Stone to explain - through the medium of song, of course.
Stone is fronting the campaign for Cadbury Crispello - and because this new chocolate is described as "a delicious, bite-sized chocolate naughtiness", they're asking people to confess their naughtiest moments on a dedicated Facebook page. Stone is then taking her favourite stories, and setting them to music.
So click play on the video above to enjoy the first one: which tells the tale of, yes, a woman putting fake tan into her boyfriend's moisturiser. And learning a valuable lesson as a result.
And if that isn't enough Vikki Stone-tasticness for you, here's another treat: her recent song about - nay, love letter to - the one and only Clare Balding, for which she's joined by fellow Balding enthusiasts Miss London and Pippa Duffy: