To preface this story and to offer some context, when my step-brother (We will call him Blake) and I were young teens, we often exercised some healthy curiosity with each other. Masturbating and talking about our changes with each other. We never touched eachother or anything like that, and those activities died off after a year, or so, for the rest of our childhood. We used to spend every other weekend with each other, as my father had partial custody of me, but that stopped, and so we went out separate ways.
Fast forward 5 or so years, I’m 18 now and, and Blake and my step-sister are 19. I’m trying to rebuild my relationship with my father, so I end up visiting him every so often, and hanging out with my step-siblings while I’m there. My brother and I hit it off again and quickly rekindle our strong friendship. We don’t mention the sexual stuff we used to do with each other, just acting as friends and brothers. Well, one night, when I was particularly horny, and Blake and I were watching a movie with some sex scenes in it, I start to get some ideas. Our sister is in the room with us, but she is across the room, maybe 10 ft, on the computer we had in the large main area of the basement where the entertainment center was also set up.