Called it.
Of course it was the strict, sexy Senpai that was the one blackmailing and controlling her cute kouhai into taking lewd photos of her and ultimately whatever else she wants to make him to do. They're so compatible it hurts.

I don't think any artist does as much justice to the Office Lady tag then Ashiomi Masato.

Ashiomi Masato knows how to draw a juicy booty on an office onee-san!

Ah, a reverse blackmailer - sorta. She does have one juicy booty. Nothin' like a thick office lady with glasses.

This is almost femdom I guess? Hard to say when it's the woman blackmailing him to take control than actually taking control herself.

Now that is an ass filled with man's hopes and dreams.

I love glasses, glasses love me!
We are a happy backmail family!

I've read one these with hypnosis related recently, girl was just faking it the whole time and enjoying getting railed and ordered around by the guy

"GOD DAYUM!" ... perhaps she may not be the "Ara-Ara" type (or might she reveal herself to be so one day), but there's No Doubt Erika-san is already a Most Excellent Combo of an FMC: Senpai (relative to the MC), Office Lady, Assertive Girl and Sexy Onee-san)!

Not sure whether to pity this story's MC (Yousuke-kun) or classify him as a Lucky Bastard, 'cause he's likely to occupy his current position (catering to Senpai's ... er, fantasies) for probably a very long time.

Hang In There, Chief ... maybe your speculations about them might one day become reality ... personally, I'm thinking Erika wants Yousuke to get more assertive himself before that happens. But for now, regarding his present status, she's definitely gone: "Hey Mikey, I Think She Likes It!"

And lest I forget to mention it: "DAT ASS!" (In that respect, Yousuke and Chief are both Men Of Culture)!

Once More, Ashiomi-sensei ... your efforts are "APPROVED!"ðŸ§ðŸ‘ŒðŸ·

We’ve been hoodwinked, bamboozled, lead astray, run amok and flat out deceived

weird shit, but typical roundabout japanese.