There was a gender swap button that Nate just pressed slightly on accident when he was browsing the options and suddenly his dick vanished as he could feel some breasts growing from his chest. Then his older sister Claire bust open the door and say "Nate, dinner's ready."
Nate flinched and said "It's not what it looks like!"
Claire asked "What does it look like Nate?"
"Um... Nothing..." Nate said suspiciously although he noted that even gender swapped her voice sounded similar. Maybe a little lighter. Nate tried to make her voice just a little deeper "Just um playing a... a ... horror game." as she tried to hide the remote behind her back.
Claire sighed she said "Well dinner's ready. Maybe wash your hands or something before eating?" somewhat guessing what Nate was doing. Then she left Nate's room.
Nate took a deep breath and looked in the mirror she had in her room and saw that her features had softened a little, but she still looked a lot like her normal male self. Then looking down Nate's boobs while a little irritated by her t-shirt were small enough to not be that noticeable... nor were her butt of hips that large... Did Claire not notice Nate just changed sex? Nate for sure went to the bathroom and got some band-aids for her nipples... and may as well wash her hands. It would be simple to just gender swap back but... There was something about getting away with such a blatant change that got Nate excited. She felt a tingle in her crotch and then remembered... She was a she and not some futa or whatever. Nate took a few deep breaths as she decided to go to dinner as a girl.
Meanwhile Claire was going down to dinner a bit concerned about her little sister. Natalie hadn't filled out like her, and was always a tomboy who liked to go by Nate. When she was a kid it was cute, but now Claire was concerned... Was she trans? She didn't seem to feel like she was in the wrong body or anything she just... was like a dude... Well she was saving a few things maybe she'd treat Natalie to a girl's night in her room.