Please remember that no matter how many times your brother-in-law yells OH BOY, RIDIN' THAT BACKHOE your child will never take it as anything but encouragement.
Like your child, construction equipment is as innocent as a babe in the woods. And like your child, those woods are full of people who know a lot of grown-up words. That's why, in this post-Sir Mix-a-Lot age, the word "Backhoe" can often bring a few giggles. That's perfectly okay. Because your child has no idea.
It doesn't matter if your little boy yells BACK IT UP or your little girl yells WATCH ME BREAK THIS DOWN or they both yell I'M MAKING IT WORK because, in their childish world, there are no metaphors yet. Things have one meaning, the literal meaning, and to them, a backhoe that you can ride is just that. Only a simple piece of toy construction equipment that is designed to support the weight of a child as they pretend to be digging a hole, ditch, or chunnel.
And don't worry if you don't know what a chunnel is. It's just a European thing. Nothing bad about it at all.