The Narcissistic Mother in law. : Parenting

TL;DR- MIL tried to manipulate us into breaking the holiday rotation so she could have both Thanksgiving and Christmas.

I am not sure if this is the best place for this, but I am hoping for some help. My husband and I both come from blended families. Scheduling around the holidays is precarious so everyone gets to spend time with us (and our 4yo) and not feel robbed. My mother in law does not feel that we should ever not go to her house. I have expressed, respectfully, that we will not accommodate that, as my family is also in the picture, and we will have to switch years, like freaking custody. So one year we do Christmas day with her and a different Christmas with my family, but Thanksgiving Day with my family. And vice versa the next year.

Well, this year we had Thanksgiving with her, so Christmas Day is with my family. She and her husband, picked the day, we would do gifts with them in the early afternoon then another round with FIL's side in the evening. When confirming the times for tomorrow(!) she informed us that she has not started wrapping our sons gifts and we should just come for Christmas Day, and her parents wouldn't even arrive until the day after anyway.

She did not tell us this on her own. She was just going to let us show up, and keep us there all day so she could manipulate us into coming back! I am so furious!

Put your baby to bed drowsy but still awake. This helps your child learn to soothe himself to sleep and prevents bedtime problems down the line.

This is not her first offense. My husband has a lifetime of examples to tell.

My hope is maybe someone has some advice for what I can say with out looking like the ungrateful psycho she tries to illicit from me. Help?