I have a question from my brother. [Details inside]?

My brother, Justin, is going to ask his girlfriend to marry him. :)
We want a really good idea of how he can ask her.
He has a few funny ideas, like “We’ll get in the bathtub, and I’ll be like ‘Danielle, you’re sitting on my ring. Well, now since your ass has been all over it, you might as well just keep it.’” But I’m pretty sure he’s only joking about that one.
So what are some good ideas for us to mess around with? We’ll probably change it up, and make it more “Justin-ish”, but a starting idea would be great. :)