There was a manga that we had here a couple of months ago. What I remember of the conceit was it was two girls who had to sneak inside of a locker at school to hide from people, and then it gets really risque with some touchin' and I THINK an ear bite? When I went looking it looked like it might have actually been removed from the reader, but I might just not be able to find it.

Is it After School? https://dynasty-scans.com/chapters/after_school_ch4_5#19