I liked this. I like the end especially, where you leave it with Rodney somewhat chastened but probably not really having learned the lesson, and John probably worrying whether he's overstepped the mark (yes) and if it'll have any useful effect or make things worse. But together with getting to trust the team over time, I think it does eventually help to get through to Rodney.
Of course, I like spanking fic and can't help but see it as a slash-precursor as well!