You know Gemma since childhood, and have always spend your days with her, playing games or just doing stupid stuff; until one day, five years ago, she asked you to become her couple, her soulmate, to which you accepted. Since starting university, she moved to your apartment. Everything was a-okay, having some "naughtly nights", where you would play with her enormous breasts and fuck her pussy, until one seemlessly regular day of Saturday, something extremely weird happens, she grew a cock out of nowhere