We were at a function yesterday and Mary told me she had to go to the restroom. I took her. When she was finished, I told her to wait a second because I had to go, too.
"Did you know you had to go?" she asked.
"I have had to go for a bit," I explained, "but I was waiting for you. I knew you'd need to go soon."
"Did you want company?" she asked.
"Were you scared to go by yourself?"
"No, honey, I just didn't want to go twice." I'm not sure this explanation satisfied her. It's much easier to assume that her mom, like her and her sisters, must instinctively use the buddy system when going to the restroom.