What is it about imagining my wife enjoying a very large size penis that gives me an erection. About 3 years ago, my wife finally hooked up with a guy who measured 25cm in length and was 20+cm around. Ever since that night I can't stop thinking about how she must have felt deep inside. He had been trying to entice her for a long time, and after much discussion bewtween my wife and myself, we decided that it would be a great opportunity for both of us, as I had always enjoyed stories about wives cheating with much larger cocks and my wife had always wanted to try one that large. She had previously had a penis about 18cm in length. She has told me he was very good in terms of technique and also came in large volumes, and it really excites me to think about it. Everytime I make love to my wife, all she has to do is gently reming me of her night with her stud and I almost immediately orgasm. Is this a normal reaction to have about one's wife?