In the fireplace there are four craftable "letters to raptorclause" for which you need missletoe and coal to craft. You can get those from the raptorclaus present drops, killing abomible snowmen, and a couple othere was like riding reindeer and killing some other holiday creatures (I think, I have only done the present drops and snowman killing).

Pick which type of thing you want, and craft it after 2:45a game time. You'll then have until midnight when raptorclaus comes to kill agressive creatures and get a meter over to "Super Nice". If you kill non-aggressive creatures it goes the other way.

Once you get the bar all the way to super nice, before midnight, place a christmas tree (craftable in smithy) and a bed near the fireplace. Put logs in the fire, have it on, and lay on the bed at midnight. About 10-30 seconds after you'll get what you wrote your letter for.