This plot is one with a bit of a magical element to it. In this plot I would like for you to play as the role of my crush, who was the hot and popular type who would always be hooking up with other guys, and as we start talking more and more, we eventually hook up ourselves, but once she sees my tiny dick, 3” or less, she thinks I am pathetic with it, but still allows me to cum out of pity. But, as soon as my cum landed on her skin, either by magic or some other mysterious power, her pussy became a little bit tighter, and a little bit more sensitive and wet, the same would become of her ass, as it puckered bit by bit. Her gag reflex would also be affected, as it became more and more sensitive, and her mouth would salivate more and more. All of this would happen until her body formed to be able to have fulfilling sex with me, but only me, any dicks even slightly bigger that mine would either hurt like hell, or just plain impossible to put into her pussy or ass, and any dick bigger that mine would make her immediately throw up if she ever tried to give them a blow job.