From Friend to Girlfriend

You and Bob have been best friends since childhood. You were always together when we were younger, and trusted each other completely. However, as you grew older and got jobs and girlfriends, you hung out less and less. At the time you reached puberty, you jerked off together all the time, perhaps as a way of staying friends, often times making up stupid little games to make it more fun and competitive. Bob was usually the one wanting to do that kind of stuff, and always wanted you to come up with new ideas. After you had come out of puberty, you were entirely comfortable with each others nudity, and even grabbed each others penis every once in a while to see how hard the other person was while you jerked. You never thought of it in a gay way, you were just two friends sharing porn and pleasure. That is, until Bob got an idea in his head.