Your new favorite word ('No!') has been counteracted by your new favorite activity ('Bring it to Mama!'). You have discovered the apparent joy in bringing things to me upon my request. What's not to love about that? If you happen to get your hands on something you shouldn't have, (or, say, tear a page out of a book with the intention of snacking on it) all I have to do is smile and say 'Bring it to Mama!' You make your way over with a smile on your face and happily give up the offending item, placing it in my hand with a look of satisfaction dancing across your face. My cheerful 'Thank you!' is the only reward you seek in return.
While 'No' is forever, I predict that the inherent fun in carrying stuff over to mama will wear off relatively quickly. I'll relish this phase while it lasts. In the mean time, maybe you can teach Sadie a thing or two about fetching.
She's never been much of a retriever!