It all started last May when my stepdad's youngest brother Mark came to live with us for awhile. I think he is 27 so my mom let him have my sister Karen's room and my sister now sleeps in my room. I'm 15 and Karen is 13 and we fight sometimes but usually get along ok. Mark is a real cute guy but is real shy and stays to himself most of the time and works for my stepdad. During the week Mark is hardly ever home and I think most of the time after work he goes to the bar near our house. My sister and I are in bed by the time he comes home so we mostly only see him on the weekends. My stepdad hollars at him sometimes and he seems to come home drunk during the week sometimes and get totally drunk every Friday night. After he was here for about 3 weeks, one Saturday morning my sister snuck into her room to get something. She came back to my room to wake me and told me Mark was naked and she saw his penis. My mom and stepdad go shopping every Saturday morning and are gone for a couple hours. Karen asked me if I wanted to see Mark naked and we snuck down the hall and opened his door. Neither of us ever saw a mans penis before so for an hour or so we kept going back and peeking in at him. We stayed up late on Frday nights just to see him come home drunk. Most of the time we fell asleep because he never came home before two or three o'clock in the morning. The few times we did see him come in he was so drunk he bumped into things and could hardly walk straight. Some Saturday mornings he has a sheet or blanket covering him but my sister started pulling it off of him so we could see his penis and rear end. My sister is more brave than me and she started just going in the room after my parents leave for the store. He is always naked but if he does have a cover on him Karen always pulls it down so we can see him naked. I think it was in July when she first touched his penis with a pencil. All she did was lift it up a little bit and his penis started getting hard. He looks funny most of the time because he sleeps with his mouth open and makes funny sounds and sometimes snores. At first I was a chicken to go into the room and would only stand by the door while Karen went in. She began pulling his legs open so we can see his testicals better and if he is laying on his tummy we even see his anus sometimes. I was always afraid to go in the room in case he would wake up. After a few months I knew he was dead to the world and the way Karen would move his legs around didn't even wake him up. We both go in the room now and we don't touch his penis or anything with our bare hands but I have touched his penis and scrotum with a pencil and the handle of my hair brush. He gets an erection lots of times but sometimes doesn't. Karen got a feather and began tickling his penis and scrotum with it and most of the time now he does get hard. When he gets an erection his penis is about 6 or 7 inches long I think, but when it is still soft it is only about three inches. We try to be quiet but sometimes we do make a lot of noise mostly by laughing and he still doesn't wake up. Karen and I take turns touching his penis with the feather and thats what makes him get hard the fastest. Once he has an erection we tickle his penis on the bottom and most of the time we can see it move by itself. Before we go in the room Karen always knocks on the door and says his name but he never reponds. Its like somebody knocked him out and if he knew how silly he looks sometimes he would die. There are some Saturday mornings when he has spit up on his mouth and chin and a few months ago we could tell he threw up a little on his pillow. The one time he peed the bed but I don't think my mom found out he did. That afternoon he washed the sheets himself. Karen and I laughed that a guy that age wet his bed. He must drink an awful lot to get that bad. My stepdad don't get mad if he drinks on weekends but does if he gets drunk during the week. Karen and I go in there almost every Saturday morning and there have been times when he wasn't all the way on the bed and one time he was asleep on the floor. It was only two times when he still had his underware on but Karen took them off of him and he never moved when she did. We never stay in there longer than an hour because we don't want to get caught. I know he doesn't know we are doing this especially because he is so quiet around us and don't even talk to my mom very often. Karen isn't even mad anymore that he is using her room. He told my stepdad that he was going to get his own apartment soon but Karen and I hope he stays longer.