When Charla Muller told her friends what she was giving her husband Brad for his 40th birthday, she was met with a variety of responses - none remotely positive.

One thought she might have been going through a mid-life crisis of her own when she came up with the idea. Another questioned her sanity, and yet another asked bluntly: ‘Were you drunk when you thought of this?’

What on earth could the gift have been? A particularly hideous pair of cufflinks that light up in the dark? A speedboat so expensive that it required selling the house? A session with a lapdancer? No, it was worse.