DM visited recently. She always brings a lot of stuff with her. Always leaves things here like toothbrush, nighty etc so she doesn't need to bring things with her whenever she visits (lives far away so stays 3-4 nights every month or so). That's all fine and she has space in the spare room that is just for her stuff.
She also always brings stuff of hers like little notepads she no longer wants and presents it as a gift for me or my children, along with little things she's bought new like socks. (Although she has now also taken to 'gifting' her old socks to my eldest daughter).
On her most recent visit she brought a used bar of soap from her bathroom and left it in my downstairs toilet, along with the bar of soap I had put there AND the new bar of soap SHE put there just before Christmas. To be clear, this is not the en suite to the guest room that she uses. It is the downstairs toilet, next to the kitchen and living room.
What on earth is behind this behaviour? It's like an animal marking their territory (ie my house) or a squirrel hiding nuts all over a park. I can't imagine that sje does this in anyone else's house that she visits, so something to do with our relationship.