Ah...She already knew he uses those cock sleeves since the walls are thin and she can hear him from next door, and everytime he denied it probably only served to urge her on to tease him further.
But I do kinda agree with what she says. Sometimes, just giving in may not be so bad...
Great ending though. That dress looks great on her, kinda makes me want to see...more.
IMHO, not so much "femdom" as Aoi-san being assertive enough that she recognized Takkun desperately trying to maintain an illusion of his non-interest in "matters sexual". Good Try ... until she revealed she heard his (cough-cough) "stress relief" activities loud and clear, inclusive of her name being called. And a whole crate of onaholes, too ... DAYUM!
In the end, an onahole cannot substitute for a living breathing woman, who's quite sweet on him ... and it likely contributed towards his exam success later. Good Job, Aoi-san.