Succubus Ecchi [English], by Hitotsuba
Please, find in yourself the strength to forgive the mangaka for choosing to go with shota. Because (a) we hardly see the male MC, and (b) the girl is a TOTAL succubus babe, it would be a crime to miss on her gorgeous meaty curves.
Ahem, so, yeah, it’s a “female succubus meets a promising mating partner” story. The scenario’s unimportant, here, what mattered was the art. That succubus girl was awesome, very meaty (not plump, definitely not, but if it was possible to have a sexy curve rather than a flat line, she had it; see the idea?), with a horny face and there wasn’t too much censorship. A great fap material
The manga has been scanlated by Blue Goblin, thank you!
By the same artist, I also share Guuzen Matchmaking, Boku To Onee-chan No Natsuyasumi, Yume Utsutsu and Kyou Dakeno Kanojo.
And now, the download & gallery links 
Open the Complete Pictures Gallery
Download the Free Hentai Manga in a Zip file
(17 MB, 19 pictures, English)
Or you can also use the Alternative:
Zip Mirror #1 – or – Zip Mirror #2 – or – Zip Mirror #3
“Because Yuu-kun and I are gonna to be together forever.” – Rika-Onee-chan.
Well, provided Onee-chan doesn’t inadvertently drain him dry, and/or she somehow helps him raise his stamina level to keep up with her:

I think if I were a succubus, the horns would drive me crazy. Every day, trying to pull on your clothes and getting hung up on the horns. After awhile, you have to stop and pull your top off and try again.
And don’t get me started on brushing your hair around your horns: Thunk-thunk-thunk-thunk-thunk-thunk. (Stops, adjusts the part, begins brushing the other side. Thunk-thunk-thunk-thunk-thunk-thunk-thunk. “(Whispered) Lord, please, my head!” Fixes hair, then moves to brush the back. Thunk-thunk-thunk-thunk-thunk-thunk-thunk-thunk. “(Yells) I’m not a fucking woodpecker!” (Reluctantly reaches for the half-empty industrial size jar of aspirin.)
I wonder where the corrupter of youth left the husk.
Dat succ, filename worthy of a good chuckle.
Another succubus x shota, where shota looks like he’s 10 (or younger).
Oliver, no loli (which I approve) but shota is OK? (let’s be honest, in works like this it’s not shota, but pedo)