the ring is bought and will be under the tree?
no..no...NOOOO!... don't do that way!. wrapping an engagement ring up as a gift is just wrong in so many ways. be a man wait in till after all gifts have been opened and then pull the ring out from where ever you have it stashed and ask her. better yet ask her on x-mas eve. just whatever you do don't make it into a gift because that is not what it is.