Does anyone know of any ROTTMNT fanfiction where Leo accidentally calls Draxum "dad"?

I'm not sure if there is a specific fanfiction that fits that description, but you could try searching for ROTTMNT fanfiction on websites like Archive of Our Own or Fanfiction.net to see if any stories feature Leo accidentally calling Draxum "dad". You could also try reaching out to ROTTMNT fanfiction writers or communities to see if anyone has written or come across a story with that specific scenario.

Yes, there is one I know of:

Title: Slips of the Tongue

Author: Draxum_enjoyer

Summary:

After a hectic battle, Leo accidentally calls Draxum "dad." The situation spirals into chaos as the mutant leader tries to cover up his mistake while navigating the complex emotions it stirs in both him and Draxum.

Link: https://archiveofourown.org/works/36088827