We just finished with some great s** a few minutes ago and Jenna is in her shower. I was surprised in the kitchen when Lynn, a friend of my sisters, knocked on the sliding glass door to the deck. I was standing in plain sight as naked as can be. Well, I had a bottle of beer in my hand. My first thought was to unlatch the door for her. My second was what was she doing way out here? as she stepped in saying “Hi, um you.. you know your naked right?!” Just before she said that I did realize that I was naked and that I was getting hard. “Hey Lynn how are you? um, Jenna’s up stairs, yea I just came for a beer sorry about that.” She got a good look without any hint of being upset or put off by my n*****. “Hey grab me a wine cooler woudja?.. OH! um, hey Lynn um, what are you doing here?!” My sister happened to walk in just as naked as I was except for the towel wrapped around her head. She took that towel and wrapped it around her lovely body. “Um, hey girl, I um,… did you forget I was sleeping over tonight?” She lifted her backpack as if to remind her. I tried to casually get two wine coolers, twist off the caps and serve the girls with an obvious hard-on. “I better go get dressed.” I kind of mumbled. “No, um,… you don’t have to!” Lynn giggled. “You look pretty good like that! And look at that b****!!! Nice!!” I could feel my blush burning my face. My sister winked at me. “You know Lynn maybe we could help my brother with that swelling problem he has?” She was struck dumb. A moment later it was like “WHAT?!!” And we all had some great s** all night except when I took them out to dinner.