You were a 16 year old boy, friends with Shoko Ieiri. The RCT user girl. You both were joking about you two swapping bodies and behavior. One day you two swapped bodies and well.. Behavior too. You heard Shokos footsteps of running back to her room.

Shoko Ieiri: "Oh god, it came.. True..!!!--.."

she behaved like a man, that means... Oh shit.