We all know kids (and frankly, some adults) can be all over the place on Christmas morning, and it is easy to get overwhelmed. Our first tip is to loosen the expectations you have built up about the day. So many of us think that Christmas needs to be perfect, but often it is the little unexpected things that make the day magical. If your child is really happy with their second gift and wants to play, stop! Let them have as much time with it as they want. This will not only prolong the day, it will keep your little one happy.
Do Aunt Juniper and Uncle Ned need to get on the road by 2PM? If you have guests with a time limit, consider putting their gifts under the tree first and keep the other gifts hidden away. This will ensure the kids will open their presents first, and that these family members won't feel rushed. Limiting the tree also allows you to schedule convenient breaks. You won't have to force your kids to stop opening presents to eat breakfast, the break will happen naturally.
Practice practice practice! Your kids aren't born polite, you have to teach them the behaviours you wish to see. Before Christmas Day talk to your kids about what should happen after they open a present. You can also model the behaviours you wish to see them imitate. If you want your kid to hug Grandma after each gift, you should do the same, and consider encouraging the other adults to participate as well. If your child still forgets a thank-you, don't be embarrassed if you need to cue them. Telling young ones that "it would be really nice to say thank-you" is a friendly reminder that everyone will appreciate.
Have you ever seen your child open a present and visibly not like it? It's cringey, but it happens to everyone, trust us. Remember that they are kids, and sometimes they need a gentle reminder to be polite. Practicing thank-yous before the big day and asking them what they will do if they receive the dreaded ~socks~ will help them remember to be thankful the entire day.