Dewi tries to spend Christmas Eve with his significant other if he has one that year, doing whatever they're interested in doing (video games, movie, shopping, etc.). Then hopefully he spends Christmas with his parents. They're frequently out of the country, so there's been a few years that he's spent it alone though they always try to be back in time. When they spend it together, they order those pre-prepared holiday dinners that comes with everything for a decent size family meal, you just have to bake some of it and enough cookies to feed an army. Then they hang out, watching movies or playing games, that kind of thing. They exchange gifts, but it's more like "open when you get around to it" as the focus is each other's company.
The twins (Lucius and Blake) spend the holidays (definitely Christmas, the days before and after if they can) with their parents and little sister. There is a lot of baking done, usually with two or more people. Most years, they make excess to donate to a school event, the local homeless shelter, or even just those nice neighbors who... While purchased gifts are allowed, one of their rules for presents is at least one thing you give each person must be made by the giver. Gift exchange is done after breakfast if everyone's there, after lunch if they have to wait for anyone to show up. Someone is designated "Santa's Helper" and they're in charge of handing out all the presents before everyone takes turns opening up one gift at a time.
Satoshi's parents insist he has to spend the day with them, not that he wouldn't even if they didn't request it. December 1st, their "required family time" is spent picking out and setting up their Christmas tree. December 2nd is for decorating the tree and on December 3rd they decorate the rest of the interior of the house. The outside of the house is left for whenever the weather permits it and is mostly done by Sato's father, with minimum help from the others, as he best understands the electronics involved in the displays. Christmas consists of all three meals at set times, a gift exchange (when he was really young, all the gifts were for him and his parents exchanged their gifts after he went to bed), a time where he and his dad just hang out tinkering with some stuff, and (weather permitting) a three-way snowball fight followed by hot cocoa and cookies.
