First translation. I've gotten tired of poorly uploaded, non-edited, lazy MTLs lately so I decided to actually put a large amount of effort in this one.

Thanks for the translation !

Base +6, Enigma613 +6, KidA111 +6

quite an interesting work. good TL too

Base +11, Enigma613 +6, LingeringMemories -15

good translation

Base +1, LingeringMemories -15

>I've gotten tired of poorly uploaded, non-edited, lazy MTLs lately so I decided to actually put a large amount of effort in this one.

Are you trolling or being for real?
I'll play the fool and pretend you're being sincere, but there's a LOT of room for improvement.

1.
The original files were 3031x4272, and you used 1280x1804. The site automatically scales down images to 1280px by default, so you need to make sure you're downloading the original archive, otherwise you're losing tons of quality.

2.
If you're not going to properly clean and redraw the cover, honestly leave it as is. It looks like complete shit to use whatever auto-fill/content-fill tool you're using. You're saying you're sick of non-edited and lazy MTLs, and this screams of being non-edited, lazy, and a MTL. Also, the RAW includes a textless version of the cover with a filter over it, so in terms of redrawing or recreation with color shifting, you had basically a free cheat sheet. It's like having a rear-view camera in your car. Extremely useful tool, but you need to actually use it.

3.
You clearly used some low effort auto-cleaning program or used a content-aware fill brush to clean the text. It creates tons of smudging and looks terrible. You should try cleaning every box manually. It takes 0.5s to use a white brush on normal boxes, and for translucent boxes with background, you won't smudge the lines. You should then be redrawing the art in translucent boxes. If you can't do that, then tbh doing a full clean of the art too would still be better than whatever tool you're using to avoid smudges.

4.
Use a better font and learn proper spacing and sizing in text boxes. In order to be read easily and look good, text should use comic book fonts. Yes, the same font you find in Western cartoons. They are used for a reason. English is not Japanese, you can't just use whatever font you want and expect it to look good. It would take 5m to look up what fonts are commonly used as well as why. Text should have clear margins and certain shape inside bubbles.

5.
Be honest with me. Do you know Japanese? Do you know English? Or is this actually just MTL'd? Just from the title, there's many problems on both fronts.
とある夏休みの膣内放尿練習日誌――僕の大好きな瀬尾さんを小便器として使用した28日間
First of all, the title is broken into 2 sections. The first is more of the main title while the second is like a subtitle. These are two separate lines and should be separated in your title.
練習 is Practice/Training/Drills and 日誌 is Log/Entry/Journal/Diary. I'm gonna be honest, I haven't read this yet, but the context of the full work will determine whether you want to use "Practice Journal" or "Training Log" or so on.
膣内 is "intravaginal", which is commonly used in doujins for creampies or to feel things from inside the vagina, etc. In most cases, using "inside" or "internal" is a good choice because intravaginal sounds completely unnatural, however, in this case, since the title is framed as a scientific study journal entry, I think it actually makes more sense to just use "intravaginal" and be more clinical about it.

So my take on the title would be something like:
A Summer Vacation’s Intravaginal Urination Training Log — 28 Days Using My Beloved Seo-san as a Urinal

6.
I'm not going to go through the rest of your work because I don't work for free, but based on the title alone, which is arguably one of the most important things to translate, you either have some problems with English, Japanese, or both.

I do really hope that you're just unaware, so good luck moving forward if so.

Base +11, Shinryu-Rex +11, KidA111 +6, EricWolfan214 +13, damiao +6, edemaruh +6, Telaneo +9, DearGoddess +12

Wow, she's a keeper!

(Wish the MC would've manned up a bit more and peed inside her at least more than only once, that's all she wanted, but beggars can't be choosers)

Base +6