please tell us the name
Or link if you can ლ(´ڡ`ლ)
It's one of the compilation shorts of dagong ikseon, just search 다공 익선 and it's the last short
Official website - https://m.mrblue.com/search/?keyword=%EB%8B%A4%EA%B3%B5%EC%9D%B5%EC%84%A0
Not official website -
https://newtoki319.com/webtoon/25161506
https://zinchanmanga.net/manga/beta-count/
LOTS of ads, keep that in mind
There's a spin-off where the baby grows up into an alpha, it's not 3P but there's smut !!