I love it when my wife hasn't noticed I slammed the bus a few more inches - meaning?

In the book Dave Barry Does Japan, he notes this phenomena, and mentions that he saw one that read “King Fucker Chicken”

But if your wife doesn’t notice, what’s the point?

Seriously, if you’re sexing up the wife and she doesn’t notice a ‘few more inches’ of… well… anything really… you’re doing it very, very wrong.