Shounen Yo Daishi O Idake (“Seize The Big Girl, Young man”) [English], by Announ
That’s the magic of hentai: as a child, the male MC fell in love with a teenage girl and her massive breasts, and now he’s in highschool himself she hasn’t aged a year and she’s openly welcoming his sexual propositions. I’ll spare you the scenario’s details, they’ll be up to you to discover ^^
That’s the dark magic of hentai: sometimes weird things happen under a mangaka’s drawing pen, for instance the relative body proportions occasionally becoming out of sync (on one panel the MC is normal, on the other he’s dwarf, the first time I almost burst out laughing )
All in all, the read was worth it in my eyes, a thick lovely airhead with giant boobs, and a vanilla story type, it was good ^_^
It’s been released by Ingloo, from Scans For Humanity, thank you!
By the same artist, I also share Zettai Ryouomoi Appli ~ Anoko No Kokoro Mo Karada Mo, Katte Ni Ore No Mono.
And now, the download & gallery links 
Open the Complete Pictures Gallery
Download the Free Hentai Manga in a Zip file
(12 MB, 25 pictures, English)
Or you can also use the Alternative:
Zip Mirror #1 – or – Zip Mirror #2 – or – Zip Mirror #3
Your poor translation of the title completely misses the William Smith Clark (1826-86) reference/pun.
if by that you mean the “Seize the moment, young man” quote, then i wouldnt say it does, since you either are familliar with said quote, and it will trigger recognition, or you aint, and then it just becomes a pretty fucking litteral description of what happens.
I apologize most profusely that my knowledge of English literature culture isn’t good enough, and I hope you are not only blessed with superior intellect, but also with praiseworthy kindness, and you can find in yourself the strength to bestow upon me the knowledge I pathetically lack.
AKA the fuck man you expect me to know everything, so don’t act allmighty and fucking tell me what I missed instead of acting all superior like you’re shitting diamonds when you’re in the loo, and also might you consider the scanlator chose this title on purpose because, say, it might be related to what happens in the manga?
Ah, memories:
https://youtu.be/ZjdC7WGvSWU
Geez, it’s like he’s involved with a shape-changer with poor self-control. One minute her head is tiny, the next her clothes are skin-tight. Suddenly she fills half the room while he’s perched precariously atop her, trying to kiss her suprisingly correctly proportioned mouth. Then her breasts morph and he’s teetering on the brink of her vagina, his voice echoing off the far wall. He’s in danger of getting sucked in, then suddenly she has a huge load dripping out, like he wasn’t 1/10th her size a minute ago.
I admire the author’s passion, but holy crap, consistency is more than a game winner in Scrabble!