I'm not great with Kanji, so when I started translating this I thought her name was Ritsuko (which kind of makes sense with the Hiragana for her nickname being Ritsu-chan, though I've noticed that often that tsu ends up being more like a dash than a sound). But when I got to Ch11, they actually had her name in both Kanji and Hiragana. That made it clear that her name is indeed Rioko. Even so, I really like her as Rit-chan. So I'm keeping that as her nickname (for some reason I just can't get into Ri-chan).

It's not that obvious, but there are 3 guys in this story. One of them is behind the camera the whole time and he doesn't say much (his lines are underlined). Too bad they had to end the video there, would have been fun to see Rioko taking 3 dicks and getting a nice bukkake.

So far as I can tell, the anal / phone sex mentioned here doesn't have a chapter. Although part of that story is told in Ch4. I did a quickie translation to see if it interested me, but I wasn't too into it (especially since the second half featured a Mom who looked like a Loli, and there was quite a bit of handwritten text that I couldn't read). It was nice to see a cameo from Yoko and Kaede though. And is that Tomokazu they're fucking? Too bad I can't read their dialog.

The summary of Ch4 is: Tomokazu sees his Mom meet up with the kid and remembers that after he saw the video in Ch1, his friend offered to let him join the club. Soon after that, they let him see all their videos. Included was his Mom's first time meeting the kid and taking his virginity. During that scene she say's Tomokazu is at training camp for his club and talks to him on the phone. So the anal sex should happen after that. But the story ends without showing any of it.

I'm working on Ch2 next (Tomokazu looses his virginity with Saki-san, one of the club Moms). They mention his girlfriend again in that. That's the one thing I found a bit odd in this one. They casually mentioned she was probably cheating on him, but neither he nor Rioko has much of a reaction. Maybe Tomokazu didn't get the implication there because he's still in shock about his Mom. They do deal with it a bit in Ch2 though.

The story teased at the end of Ch1, where Rioko and Tomokazu go out together next weekend, doesn't seem to have happened. Instead he creeps up on her while she's sleeping in Ch7a (presumably that's this weekend after making his way through all the women on the memo he was given).

She tells him no anal until she has time to wash her ass. Which is very nice of her considering she doesn't like it and the fact that's he's pretty huge. Maybe she got used to it in that 3-man gangbang after the camera got turned off.

There's another chapter that isn't in the numbered list from the poster of the raws. I'm calling it Ch7.5 and it's titled Haha Anal / Mom's Ass. Her sister catches them getting it on, passes out and ends up watching them continue. (Too bad it's not colored.)

The lady on page 57 is Saki-san, who shows up in Ch2. I haven't seen the others show up anywhere though.

Series list form the original poster:

#1: Okaa-san to Otomodachi - https://e-hentai.org/g/1098082/4c42c70859/
#2: Boku to Dareka no Okaa-san - https://e-hentai.org/g/1098074/266e8cb6a0/
#3: Haha Baba - https://e-hentai.org/g/1098092/72cc3b5b29/
#4: Okaa-san ga dokoka no ○○ to suru no de, Boku mo Dareka no Okaa-san to shimasu. - https://e-hentai.org/g/1098130/be96ee33c8/
#5: Okaasan ga Hidoi Koto o Iu node, Hippa Taitara, Yaru Koto ga Dekimashita - https://e-hentai.org/g/860619/dd873ea629/
#6: Natsuyasumi, Dareka no Kokujin Okaa-san to - https://e-hentai.org/g/1098148/4d76b4262f/
#7: Boku to Okaa-san: Natsuyasumi, 7-gatsu 28-nichi, Gogo - https://e-hentai.org/g/1098240/b6d81e9e36/
#7.5: Haha Anal - https://e-hentai.org/g/881478/38a5b88782/
#8: Minna de Otomari-kai: Senjitsu-Hen - Kahitsu-Ban - https://e-hentai.org/g/1098522/60cac5a982/
#9: Haha wa Kakushi, Boku wa Shiranai Furi o Suru - https://e-hentai.org/g/1065316/d836a61026/
#10: Omae no Mono wa Ore no Mono - https://e-hentai.org/g/1098895/532deb1f61/
#11: Boku to Okaa-san to Otokonoko to Boshi Rankou Circle - https://e-hentai.org/g/1065314/19ecc0e59f/
#12: Boshi Rankou Circle - Shinki Nyuukai Boshi - https://e-hentai.org/g/1065264/8b8059aad6/
#13: Hahaoya Koukan - https://e-hentai.org/g/1065306/7486a0af29/
#14: Umi - https://e-hentai.org/g/1065302/b52c94f28f/
#15: Okaa-san to Otomodachi to Toilet no Anako-san - https://e-hentai.org/g/1115424/ef47fceca7/