The Messages.

It's a story where Barry Allan and Clark Kent hangout and eat a meal together, but then they are needed to save people's lives. During the team up, Clark gets infected by Red Kryptonite, which slowly changes his behavior and as Barry tries to take Clark to the Fortress he begins to notice the changes in Clark behavior. Superman gets aggressive and wants to hurt Lex Luthor, but Flash tries to calm him and stop him, which is when things get feisty. May lead to a ship between the two~ or it may not. Either way, it will bond the two closer to each other.
The characters are from the comics version and not from CW or DCEU.
I do not own the characters. DC comics does.
A story my friend, Kyran, and I have been working on.~