Future Sense tells me Chapter 5 is conquest of the older twin sister. Then Chapter 6 will be the glorious foursome family orgy.

Base +7, shad0ww -6, SkullDraecos +6

Chapter 5 is already out in Japanese, so there's no real future sensing involved there. You are correct on what happens though.
Chapter 6 is still another year off, give or take a couple months, given the rate of release on this series.

Base +6, shad0ww +6, AhKai +6, BFBK +6, dabrhe +6, Porokichin66 +9, SkullDraecos +6, idiotwithacomputer +6, hm4ster +7

Page 12, that upside down holding pose is peak!

Base +9, SkullDraecos +6

Thanks translation!
Really enjoyed Fukuyama Naoto succubus defeated by dick.

Base +10

So that size is just his default now

Base +6, docterderp +6, clamdown +7

Fukuyama Naoto - Succubutic
[English]
Chapter 1: https://e-hentai.org/g/1777021/cc752b0801/
Chapter 2: https://e-hentai.org/g/2310051/102adeb4f5/
Chapter 3: https://e-hentai.org/g/2316589/a5026be66c/
Chapter 4: https://e-hentai.org/g/2771498/cf1db7a3c8/
Chapter 5: https://e-hentai.org/g/2775163/2528b06250/

Base +16, Celibate_Wanker +14

She was dancing through all of that shared sesation?!

Base +6, Sen1oriln1k +5