Not sure if this is the right place but I tried r/tipofmypenis and got no response. Not sure if they do stories.
This was a story I found online years back (more than 10). It was about a doctor who wanted to do a sort of social experiment. He found a family with adopted children and when the son came in for a check up he said to him and the mother that he had a rare condition where he had to cum multiple times a day. He couldn't jack off though because of… reasons. Can't remember why. Eventually his adoptive mother, sister, and their friends all help him. There was a bit where his sister, who is a cheerleader, has him paint on panties for her and the other cheerleaders before a game so they can distract the other team.
It had a few anime style pictures in between chapters. I lost the site name after getting a new computer. Don't even know if it still exists. Was hoping someone at least saved the text somewhere. Would greatly appreciate any of it even if it's just a few chapters.