The events I am about to describe took place near the end of this past summer, I am 19 and my step brother is 14, his mother and my father had been married almost a year back in August. I got along well with my step brother (and still do)we talked about a lot of things but we had never talked about anything even remotely sexual.
Once we were looking at a swimsuit calendar together and talking about how great the girls looked in it, I tried to bring up the topic of masturbation but my step brother 'Marcus' seemed offended that I would even think he did that type of stuff, so basically he denied that he ever masturbated and that conversation was over real quick and never brought up again.
'Marcus' has a very good friend named 'Jason' when Jason would come over every once in a while, I was always curious if they played the same type of R rated and X rated games I played with my friends when I was around the same age.
Once when 'Jason' came over I decided that I would catch them in the act and then pretend it was on accident. It was 1am and they were still awake and I swung 'Marcus's' door open hoping to catch he and 'Jason' in 'adolescent sex play' as described by my college text book. I did not want to join in but I just wanted to confirm my suspicions. Anyway when I swung the door open I found both of them fully clothed playing a video game and they were not shocked at all. I was disappointed because I was sure I would see something going on.
One reason I had been suspicious is because once when 'Jason' had came over they were playing 'truth or dare' sure they were not doing anything x rated but in my experience when nobody is around 'Truth or Dare' quickly turns x rated.
I went to a yard sale and bought a voice activated tape recorder, my original purpose was to use it in my college classes but the night after I had bought it. I thought of another use for it. 'Jason' had come to spend the night so before they went into the room that night I hid the tape recorder in a spot that I didn't expect them to look for it. The next day I went and got the tape recorder out of the room and listened to it while I drove my car.
I was excited when it first started because I didn't expect it to record their voices so well but became quickly disappointed as all I heard was the radio, video games and them talking about things that were not even remotely sexual. The last 11 minutes 32 seconds of the tape was a gold mine though. My step brother 'Marcus' said 'You must have a big ass boner I can see it through your sweats' and his friend asked 'Do you want to play truth or dare?' and 'Marcus' asked 'Regular or nasty dares too?' and his friend said 'both'. So while I am driving around listening to this I am getting so hard I just wanted to pull over and wank, I turned the volume up all the way as 'Jason' dared 'Marcus' to 'hump the pillow for 10 seconds' 'Jason' counted backwards from 10 and then my brother dared him to suck his dick for 10 seconds and Jason bargained down to 5 seconds. 'Marcus' stated that what they were doing was not gay because they still liked 'chicks' and everything. 'Jason' asked 'Marcus' if he had seen me 'jack off' and he replied 'no', 'would you want to?' 'Jason' asked and he replied 'no' That was cool with me I had never wanted to jack off with my brother just get evidence that he did jack off and I had it.
I have listened to that tape so many times and have even made 2 copies of the last 11 minutes. I could transcribe everything word for word on if I wanted to, just before the tape shuts off my brother says 'Let's wait and cum at the same time and see how much we can make' and 'Jason' replies 'Dude...' and the tape ends. Later I bought a baby monitor and I am thinking about using that next time one of his friends comes over and spends the night.