It was the Entertain District Arc, Gyutaro trying to kill Tanjiro...it's all fake and they're just acting like it
With the Actors
Gyutaro: chasing Tanjiro STOP RUNNING! yelling
Tanjiro in his head: He's on my a**, I'M DOOMED!
When Gyutaro's scythe was about to hit Tanjiro's eye, Tengen blocked him with his knives.
Tengen: NO! BACK OFF MY N*GGA TANJIRO!
Gyutaro: jumps to back WHAT?! lands HOW ARE YOU BACK?!
Tengen: YOU MUST'VE THOUGHT ME AND TANJIRO WAS P#### HUH?! NAH, N*GGA! ME AND MY N#GGAS AINT SETTLING FOR NOTHING! rushs to Gyutaro
Tengen in his head: Listen to where his attacks are coming from! AWWW I SEE NOW B#TCH! goofy ahh laugh
With the Actors that doesn't show up yet
Mitsuri: Kamado-kun, cheer up!
Shinobu: Ara ara~ Gyutaro and Ume- I mean Daki will lose, but they still acts hardly...
Giyu: You're right.
Gyokko: I just arrived?
Muzan: Your f##king late.
They didn't noticed the My Hero Academia actors just entered their studio by mistake.
Back to the actors on stage
Tanjiro: running behind Tengen I'M BEHIND YOU UZUI!
Gyutaro: MIND YO OWN BUSINESS, LIL N1GGA! stabs Tanjiro by his chin
Tanjiro: THAT SH1T WAS WEAK! I CAN DO THIS! I'M THE BIG KAMADO, THE ONE AND ONLY! slicing Gyutaro's neck with Tengen
Tanjiro, Zenitsu, Inosuke yelling