Nagito Komaeda x Fem! Reader (Smut)

You and Nagito have been close friends since childhood, enduring every tough moment, choice, and difficulty together. When one of you fell, the other picked them up.
You both happily attend the glorious Hope's Peak High School, Nagito being claimed as the Ultimate Lucky Student and you being titled the Ultimate (T/N).
It was recently your (age of consent) birthday and you invited Komaeda to sleepover at your place to munch on some cake, to play board/card games, and to celebrate for the rest of the night. Without a second thought, Komaeda accepted your invite.
But neither of you have been willing to share your feelings for each other up until tonight where one of you wins a game of Go Fish and one of you loses.