Tanjiro aproached Genya to ask for his cell phone to do something quickly since Tanjiro's cell phone had run out of battery,When Tanjiro turned on Genya's cell phone he saw that Genya had a photo of a sleeping Tanjiro hugging a stuffed animal in the background.

Tanjiro: "U-uh?!

Genya: "oh We have that photo as a blocking background"

when Genya said "we have" Tanjiro blushed even more and went to the room where Tokito, Zenitsu and Inosuke were eating,Tanjiro told them that if he could see their cell phone lock backgrounds, when Tokito Zenitsu and Inosuke showed him their backgrounds, they actually had the same photo as Genya