I wonder if it's possible to securely attach it to the bottom of my shitter...
Definitely! You'll need to drain the water out first, use some sandpaper to partially remove the glaze where you'd like to affix the coin, and to rough up the coin itself. Then JB Weld or super glue will likely get you where you're going!
Like parents actually parenting and activating the built in restrictions for their children's devices?