Drowning in Cold Blue Devotion

Gojo accidentally dials the reader, his former student, while very vocally masturbating to the thought of fucking her. When Gojo realizes his 'mistake' he goes and says hello in person the following day. Resulting in the reader learning Gojo's closet full of dark secrets comes with its own card catalog.

The plot you're not really here for: Despite the odds being against you, you've made it to Grade 1 with a previously unknown bloodline ability. Unfortunately, your success comes with some unwanted complications at your promotion celebration, during which Gojo gets uncharacteristically drunk for some reason... leading to an interesting change in your relationship with him.

And a mild kidnapping. The two things are related.