My wife and I were sleeping at my sister in laws for the weekend, It was summer and they had a pool, so we were all swimming. My sister in law is very pretty, and I always thought she looked great in a bathing suit. Anyway, after swimming, I went in the house to change. Someone else was using the bathroom, so I went into my sister in law's bedroom. I stripped down, and I was completely naked and about to put on my underwear when I heard my sister in law come in the house. She was in the kitchen talking to my wife. The bedroom door was not closed all the way, it was open a crack so I peeked through. I heard her tell my wife that she was going to get changed. For some reason, I got a rush out of the idea of her seeing me nude, so I just stayed naked. I moved back from the door to the middle of the room. My heart began beating as she approached the room. She opened the door and got a full view of me. She laughed and said she was sorry and quickly closed the door. I got dressed while hearing her and my wife laughing. When I left the room she apologized again and said I need to shut the door all the way. I told her it was no problem. Then as she passed by me, she said "boy, I didn't think the water was that cold," My wife and her burst out laughing. I wasn't that amused. The water wasn't that cold, and I didn't think I was, well, you know, in that bad a way. On the way home I asked my wife what the deal was. She said it was nothing, that they were just having fun. I should have left it at that, but I pressed. I wanted to know what she said. My wife protested. She said just forget about it, but I persisted. Finally she told me that Michelle (my sister in law) thought I was small. I said "what do you mean?" I kept at it and my wife was getting annoyed. She finally told me "look honey, I love you, but you aren't exactly Godzilla down there". I was really embarrassed now, and kind of angry. I said the water was cold and she said sternly. "no, it really wasn't. Next time lock the door". I then stupidly started a fight over how big her old boyfriends were. She told me to drop it, but I wouldn't. When we got home I persisted. My wife was really pissed now. I asked her flat out to tell me where I stood. I then took out several cucumbers from the refrigerator (like an idiot) and told her to show me. She finally said "fine, you want to know, pull down your pants". At that I said no. She "fine, then let it go", but I couldn't, I said for her to just tell me, and she said no over and over. Finally, I pulled my pants down and said "Ok, fine, show me". She said I was an idiot. I was now naked in front of her, so I started getting aroused. We argued some more. She was really angry and just wanted to go to bed. I kept at it though for some reason. Finally, she grabbed my penis, and got me fully aroused. She then went into the kitchen and came back with a cucumber that was about twice he size of me and held it right along side of me. She said "there, happy now?" I always lock the door now.