I'm really getting better at disengaging!  Today, I heard my SO's phone ring while he was in his man-cave and knew it was probably SD since he had already talked to his other family members. 

SD had sent him several personalized grandpa-type gifts as well as a small household appliance for the two of us,  (The household appliance thing is now her standard generic gift to "us" each year.  It's usually something we have already or have no need for.)

I knew my SO would probably try to get me to talk to her on the phone so I could thank her for her gift.  Nope, not doing it but I didn't want to be rude.  So I did a quick holiday hop into the bathroom and took a nice, long leisurely shower.  By the time I got out phone call was over!  

SO said something about how SD asked to talk to me but then he saw I was in shower.  Oh well, too bad so sad.  As far as I'm concerned it was just another step on the disengagement stairway.