So I read this years ago and i'm wondering if someone can help me. It's about two high school girls, one blonde haired and the other black (the black haired one is more dominant). The blonde haired one is younger and the black haired one is older I think. The black haired one left school (graduated?) but came back to see the blonde one and ends up doing stuff to her on the school desk. I'm pretty sure it was a one shot but I seriously can't remember the name.

The only thing I can remember with a dominant black haired girl on a desk is a one shot by Nanzaki Iku called Love Prep Room. She doesn't come back after graduating though. It's a couple years old, at least 6 years old now. Any other details?