Hmm, let's see if I can make sense of this idiot. Agawa completly wrecked the confidence he built on the instructions and example of this bitch, so he can't engage with sex as usual without thinking back on his crush tearing him a new one.
Hard to get hard when that's on his mind indeed.
But thanks to this surprise encounter, it was novel enough that he could experience its eroticism purely. Recreating it clumsily with the nice Prez didn't work, as he already made the mistake (?) to single out Agawa's friend as the solution.
I wouldn't be surprised if in a corner of his mind, the idea of fucking one of Agawa's close friends gets him going because it would be some way to get back at her. She might feel a bit silly and jealous if she hears that he get with her and get his mojo back.
I can get behind that move, intentional or not, because Agawa was so fucking toxic and shouldn't be listened to. The only mistake Gotou did was maybe going through the motions too much and not let himself consider Agito and Prez romantically (not sure if he had time) and ofc, listening to this dumbass Inuki for sex tips, when he was a natural!
Until Agawa think about what she's done and her feelings (at least, she's aware enough this whole thing bums her enough to stop sleeping around like usual), I can't root for them to be together. People allergic to committment stringing along everyone are the worst.
It's fine to not want anything serious and it was fine when Agawa was clear, but then she stopped being clear and then punished Gotou and denied their chemistry.