https://x.com/siokarub1
pixiv.net/en/users/6267169
https://nijie.info/members_illust.php?id=565903

https://x.com/siokarub1/status/1834283307955355670/
what to do when your favourite doujinshi has no tentacle impregnation ?
make one yourself of course
mad men really did it

Base +45, Hayketo +24, 2Forward1 +6, nhami +10, ADIN0 +10, Barzupled +8, darklord1235 +9, Maxer123 +6, blaqkthespian +6, peepist +6, Phat94 +7, VastJobber +5, The14thNoah +13, and 14 more...

So love the use of the tentacles wrapping around her waist to secure itself to her pussy, to ensure a proper seal to prevent leakage of cum.

Base +5, Hayketo +24, LUIGI-DUDE +8, Veroxious +6, hakuryu2250 +24, UnlimitedBlades +6, Gaymegun +6, henta1lover0 -6, ayashi9 +6, TanoshiMoose +6, 2Forward1 +6, qwerty5715 +6, Maxer123 +6, and 2 more...

This is absolutely top tier. Is there any name for the fertilization of eggs still in the ovaries?

Base +6, pactagon +7, Hayketo +24, Porokichin66 +9, hakuryu2250 +24, Lucifuge +6, Mr. Xecret +7, Orengestar -8, Gaymegun +6, henta1lover0 -6, 2Forward1 +6, qwerty5715 +6, Maxer123 +6, and 4 more...

Do a Parody tag search reveals Mahou Shoujo is practically its own industry

Base +7, ADIN0 +10

Is there any other doujinshi described forming the embryo like this?

Base +6, Mr. Xecret +7, hakuryu2250 +24, ADIN0 +10