Translated and edited by me.
Thanks to pundeiu for a few lines.
It was a tough one, both editing and translating wise, so it might be off sometimes.

Raw:
/s/9439c0700e/795240-84

Big sister vanilla anal. MY ONLY WEAKNESS

Base +4, Sosenem +4, Forestman +6, TheOneWhoScans +5, letum1 +5, oneiwonder +7, anaxagoras +6, DarlaMC +6, SuperStickman22 +6, jfragrettel +7, MiD0Ri +1, Kalrkirata +6, GNU/Linux +14, and 15 more...

THE BUTT CONNOISSEUR STRIKES

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I would only suggest changing the font for the text boxes, but overall it was pretty well done...
Thanks for sharing!

Base +19, Ice_Cream +12, Miriah +7, hazari_13 +3, jfragrettel +7, MiD0Ri +1, BlueSmoke +5, ZDU +7

Wow, now that's what I call quality! Nice

Base +6, DarlaMC +6, jfragrettel +7, Dorseen +2, ZDU +7

I like anal as much as the next guy, but I'm kind of disappointed that they didn't go all the way.

Base +7, McWeaksaucey +4, jessica702 +6, TheOneWhoScans +5, hazari_13 +3, BiggusDikkus -6, exia45 +6, anaxagoras -6, DarlaMC -6, Hugh Jarse +6, jfragrettel +7, imonlyhere4porn +4, MiD0Ri +1, and 6 more...

@Hakrei
Which font are you talking about? Like for the first bubble: "This is abrupt but..."?

@Drous
Thanks. Well, no need to update I guess. But thanks anyway.

Base +18, jfragrettel +7, ZDU +7

Thanks for the translation

There are 3 lines that sound a little weird

Page 6 : Could she be the type that feels it from the ass?
Should i ... stick a finger in?

Page 7 : How could a girl not wake up while her butt is getting massaged?

Base +6, jfragrettel +7, ZDU +7

>Bam? Here is young tight meat, not caring about what I assert.

This is almost poetry. Also, ASSert. Heh.

Base +13, TheOneWhoScans +5, oneiwonder +7, jfragrettel +7, MiD0Ri +1, Shinryu-Rex +6, BlueSmoke +5, nightflight7 +6, Deorem +6, ZDU +7, firedragon89 +12

I'm not one to look a gift horse in the mouth, but perhaps getting a proofreader would help out your translations? I believe the font Hakrei was talking about is the font that you used to signify that the younger brother was narrating. I'll also give you some examples of text that seems a bit off in english. On the third page the line "Since she's like this, that's always I who clean her room."

It would sound better like "Since she's like this, it's always me who has to clean her room" or for the second part of the line "it's always me who cleans her room."

And the next page "It drives me a bit angry" would sound better if it was "It drives me a bit crazy" or "it makes me a bit angry"

Same page "So, which trick could I play to her?" would sound better as "So, which trick could I play on her?" or "So, which trick should I play on her?"

Same page "Has she gain weight?" Would be better as "Has she gained weight?" Etc Etc. I don't want to fill this whole section with proof reads, but I could always send you a private message later if you'd like some suggestions to improve your script.

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Brother thinking while doing the deed, "I love big butts and cannot lie".

Base +6, ZDU +7, IHEART3DPD -6

Just letting all that pussy go to waste man... shame on you mr.protagonist.

Base +10, Deorem -6, mysteryaccountname -6, Chips Nanson -9, end374 -7, FunkX -4