So I went to ask Lacy what she felt like eating. I walked inside and went down the hall to her room. Now I don’t know what I was thinking, but when ...I got to her room I walked right in without knocking. This really wouldn’t have been a big deal before, since she was always just my LITTLE sister, I had never needed to knock. But over the last 12+ months, while I was becoming a man, I guess I hadn’t noticed that she had been becoming a woman. I walked in and started to ask her what she wanted for. I was not a fan of condoms so I was truly thankful that Becca was on the pill. I grunted as I pounded her pussy, determined to give her one hell of an orgasm. She moaned as I thrust myself in and out of her. After a few minutes passed, I decided to switch things up."Alright, now let's see that fine ass of yours," I remarked.I pulled out of Becca, flipped her around, and yanked her miniskirt up. I stared longingly at her large ass. I raised my right hand and smacked her right cheek. She squealed. She normally wears a tight shirt that does nothing to high her popping nipples.Today was no different and she had been there for about five minutes. We were chatting about some work she wanted to do in her backyard, and I was trying to not stare at her tits that were even more on display than usual. I was almost sure she had not put on her sports bra today. How she could work out without one I didn’t know but I was enjoying sneaking glances at her protruding nipples when I could. She stopped. At first I was hesitant and wanted him to stop. I removed his hand but he came back time and time again. I became curious and decided to ignore his hand and see what he does from here. I pretended to focus on the movie as well even though we both clearly didn't by this time.He continued fumbling and my dick began to grow. It got really uncomfortable in my pants but I was too shy to pull it down. I don't know why but I acted super sleepy and slipped of the couch. But my friend was hooked on it..