I want to tell you what happened to my brother when he was five years old.
He got a bright red bike for his 5th birthday. The bike was huge. He wasn't a big kid and the bike was an adult size bike, made for a man-sized person with a bar, the old "man-bar" kinds of bikes. Ladies' bikes had a curve in the frame and men's had a straight bar that you had to straddle to get on and to stop.
I remember quite a lot of discussion in the house about the size of that bike when he got it. One parent would say, "Why did you get this? It’s way too big and he’s going to get hurt."
The other side claimed that he would grow into it and things would be fine. "Let him be a boy, already!"
Well, he loved the idea of that bike, so ZOOM . . . off he went!
Not to far into his maiden bike ride, he came to a car. Unsure of himself and how to handle his new gigantic bike, he hit the breaks with his tiny little foot, flung himself headlong into the car, which launched him forward and he whacked his business on the bar.
The whole episode happened within eyesight, but beyond arm's reach and he came home proclaiming, "I whacked myself on the bar . . . I whacked my tallywhacker."
And for the rest of my brother’s life, he called his boy-parts his "tallywhacker".