Marty finished another post to the "trad incels" forum. This one expressed his dismay that another woman he had been attracted to was with a "chad." (Marty had never actually approached the woman, but since he knew that she could never be attracted to a gamma male like him that didn't matter.) Without any real anticipation he brought up his list of porn site bookmarks and began to decide what to jerk off to today.
"Hello Marty." Marty should have freaked out to hear a stranger's voice in his stepmom's basement apartment, but there was something so appealing about it that he turned his eyes from the screen, only to see in actual, three-D reality the most beautiful and sexy woman he had ever seen. No man can see a succubus without growing instantly hard. The succubus giggled. This was fun!
"C'mon Marty, time for you to lose your virginity." He was already on her for his first, and although he did not know it, his last sexual encounter as a male. As he pumped away (not much technique here, the succubus thought, not that it mattered) his body grew softer and rounder, and his fat moved from his belly to the chest and hips. He thought the internal sensations he was feeling were part of having sex, but actually a womb and ovaries were growing within his body. At the moment of climax his penis disappeared and her vagina opened up.
"I'm a girl?" somehow Marty didn't feel too surprised. He had known that there had to be a catch.
"Yeah" said the succubus. "It's not like you were making a huge success out of being a man."
"Uh."
"You were always posting about how easy things were for women. Well, congratulations."
"But I don't know anything about being a girl!"
"You'll pick it up." The succubus laughed, a little high on the manhood she had drained from Marty. "The world needs another pretty girl a lot more than it needs another loser guy."