one weekend me a buddy my sister and her friend all rented a campsite at the lake. That night after we swam in the lake my buddy passed out drunk by the fire and sister friend wouldn't stop talking on the phone. So I got up to go take a shower my sisters friend told her to go ahead and go she would shower when we got back. There was 4 little bathrooms with showers but we showered together and her naked wet body immediately made hard. My sister saw it and bent down the told me to hurry up and fuck her. When I told her I was going to cum she said don't you dare pull out I slammed it in as hard and deep in her tight little pussy as I could. I sat her on the bench in the shower and ate her out until she came again. As we walked out her friend was walking up and asked why the hell we were together. I said the others were full luckily the shower had a solid door separating it and the rest of the bathroom so she bought out story!