NC for this, for reasons that will become obvious...
Our washing machine is currently broken. MiL (who is kind and lovely, this is not your average MiL thread) offered to do a couple of loads for us, so we took a suitcase over today. I put the first load in the machine and then DH and I took DS out swimming. When we came back, that load had finished so she had taken it out and packed it into carrier bags for us to take home to dry. All ok so far.
I've just hung everything up now. In one of the carrier bags, on top of the pile of folded clothes (no idea why she folded them knowing I was only going to hang them up at the other end, but never mind) was a small, black COCK RING. 
Yes, it it ours (well, DH's). But I haven't seen it in years, and neither of us have a clue how it got into our laundry. There is no chance she doesn't know what it is.
We can never go to her house or see or speak to her ever again, can we?!?