While I was sleeping, I felt a very pleasant strange sensation on my dick... My sister was giving me a blowjob and making it hard. I pretended to be angry and said, "Hey, what are you doing?", but I ended up using my mouth as a practice dummy to put on a condom. It felt so good that it was still hard even after I ejaculated, so naturally I wanted to try putting it in... This is crazy, isn't this incest?