Sister nude story. There was nothing sexual about it. Hide Ad. I had been home a week for Christmas and nothing caught my eye at all just as usual. My sister only taking care of my things. At the top of the stairs I looked back at the door. I walked down to the edge and ended up striking up a conversation with nude family girl fully nude guy which just kept adding to this crazy day. But I wasn't thinking very straight at that particular time, so I didn't realize what she was doing just then. I mean we wouldn't have described ourselves as "nudists". Especially when we somehow ended up masturbating together right then and there in the bathroom. Her hips were beginning to buck and I knew she would cum if I kept it up. My balls ached as they tried to supply even more fluid to shoot into my sister.