My parents reaction! We told them by decorating the living room with "grandpa is my hero" and other grandparent onesies, a suitcase that said "ready or not grandma here i come!", a countdown til I become a grandma calendar, and balloons and stuffed animals. They were coming to visit from Michigan and walked in the door to Jesse and I just standing there in the midst of it all.
We celebrated Jon and Karly's birthday's over Thanksgiving. On top of each of their presents we placed an "My Uncle Loves Me" bib and a "My Auntie is the Best" onesie. Here is jon opening his present first.
I definitely recommend recording people's reactions. It has been so fun going back and watching these moments!