How much should an advisor (co-author) contribute to a paper?

I'm nearing the end on a manuscript and will be submitting it to my advisor any-day for her feedback. She is a co-author. My question: Is it OK to ask my advisor to contribute more to the paper (other than just critiquing)? If so, how does one go about doing this without insulting their mentor/boss?

To be clear, the paper is in overall good shape. There are a few paragraphs that need some attention. But instead of her just critiquing the paper ("this paragraph needs more interpretation") or ("add more examples from the literature"), is it ok to ask her to contribute actual sentences and interpretation?