Will answer one post at a time since i'm reading them before.
Quote from jahu
Bitou Lollipop - the age gap is right, but I'm not sure about the rest; the main couple is high school girl x middle school boy, but the female lead actually has a crush on a guy her age and that guy is an ass who thinks with his lower half (at least the female lead understands that)
Yeeeah, tried to read this... how to say, the characters too facked up, disgusting sometimes, so no to this one.
Quote from jahu
Game Over (MIZUTANI Fuka) - the age gap is bigger than requested (in fact it's office lady x middle schooler), but it should be worth a shot (it's short anyway)
Kinda not what i wanted in requirements, but art is cute, so readed it anyway.

Quote from jahu
Already were in completed, though it does not what i asked for in this thread as well.
Quote from jahu
It doesn't even have any info, so skipping.
Quote from jahu
Natsu no Zenjitsu - university student x some woman who is older than him; this one kind of has lots of sex... (not my kind of thing)
Seems like this were sitting in future reads but thx for pointing on it anyway. Though i didn't get how old is she, this manga have the feeling i were looking for.
Quote from jahu
Bonnouji - appears to have the right age gap, but neither of the characters is still attending school, so the age gap isn't probably noticeable at all
Already were in complete, very good read and cute couple.
Quote from jahu
Futari no Renai Shoka - high schooler x some girl who is older than him (not sure how old she is though); woudl probably work really well, but it's untranslated...
Yeah, probably should mention that translated only, sorry.

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"If you don't remove your hands immediately, I will render you unable to biologically maintain life." - that's how all shoujo must be lol.
"Her breasts, freed from the restraint of a bra, bouncing in tandem creating a beautiful concerto." - Rika