Birthday boy (Sousuke x Reader LEMON)

This is my first 'Free! Eternal Summer' FanFiction series. Disclaimer - I do not own any of the mentioned characters nor pictures and artworks used. Shout out to their amazing creators.

Summary:
It's Sousuke's birthday and you, together with Makoto, decided to organize a little something for him. Turns out some of your plans have to be canceled, which leaves you in a pretty complicated situation. Is there any way you can fix things?

Sorry, I know I suck at summaries :')
Anyway, I hope you'll enjoy the story.