As Sean was putting on her bikini top Susan was looking around the pool area and she spotted Diana as she was drying off.
Susan looked back at Sean (Mary) and smiled as she thought "I wonder what Sean would look like in Diana's body."
Susan then turned and kept an eye on Diana as she wrapped a towel around herself, then she headed into the house, so Susan followed her.
In the house Diana went to the bathroom where she changed out of her swimsuit and back into her street cloths.
Susan waited in the hall a few feet away until Diana came out of the bathroom then as Diana was saying her goodbyes Susan went into the bathroom and picked up the towel. After getting the towel Susan rolled it up and took it to the kitchen where she got a plastic bag to put it in.
After Susan had stored the towel away where she could get it latter she went back to the party.