Some say NTR incoming. But I say, how there can be any when the relationship on both sides is based on selfish motives, when it is a... detached relationship? Worst thing that can happen, Aya can no longer validate herself by blowing hers brains out tribbing sensei, which will lead to her meltdown. A lot of course depends on how messed up in the head Yoru is, and knowing this manga's track record so far, yeah.