These are the rules of the parallel universe:

The main character can have sex with any consenting woman he desires, with no biological or social risks.
Women view sex with the main character as a pleasurable and harmless activity that does not affect their other relationships or obligations.
The main character’s female friends have a shared sexual history with him that he does not remember, creating a sense of familiarity and intimacy.
Sex with the main character does not interfere with any existing or potential romantic bonds, but rather enhances them by increasing honesty and communication.
The main character’s male friends and do not feel threatened or jealous by his encounters with their partners.
The main character’s high school crush is in a committed relationship with his friend and plans to marry him soon. She loves her fiancé and enjoys sex with the main character. Her fiancé encourages her to have sex with the main character and likes to hear about their adventures.
Act I:
Scene 1:

The NAME_1 wakes up in the parallel universe and discovers his special status.
NAME_1 goes to the gym to work out, where he meets his female friends NAME_2 NAME_3, and NAME_4.
They flirt with NAME_1 and eventually coax him into the women's locker room
NAME_1 is initially embarrassed to watch the girls undress, but forgets this as he becomes fascinated by their naked bodies.
They all go to the showers where NAME_3 begins to seduce NAME_1.
Not knowing the rules of his new universe NAME_1 askes her what her husband would think.
The girls all laugh at this knowing that NAME_3's husband would definitely approve.
NAME_3 coaxes NAME_1 into having sex with her while the other girls encourage them
NAME_1 has sex with NAME_3, and accidentally finishes inside her.
Not knowing the rules of his new universe, NAME_1 asks if they should worry about pregnancy.
The girls all laugh at this.
NAME_1 leaves confused and guilt-ridden.

Turn this into an erotic story. Go slowly, provide lots of dialog, character development and erotic imagery.