@Nightweaver20xx  
I don’t think most puns and colloquialisms translate.

@A Non Man  
Oh! Well I guess things don’t translate exactly from Japanese to English colloquialisms.

@Nightweaver20xx  
No, that’s what the kanji for “going soft in the middle of intercourse looks like.”

@A Non Man
 
There are some fans that get angry at anime dubs over that but sometimes you just have to do it (even with the subs for the anime).

@laofuzi  
Better question is, who has the higher GPA; RD or AJ?

So that’s what the kanji for “jacking off” looks like. Interdashing.

@A Non Man  
Did you fail English class or something, Rainbow Dash??!!

@A Non Man  
Yep. I can see that being a term for being lazy.

Translation posted.
 

You know, now that I think about it, “jacking off” works even better here, doesn’t it?

Do you NOT have a dictionary back home, you dam fool?!!
 
マヌケの家に辞書はありますか？！

@A Non Man  
It’s a common translation problem. Closing I can come to staying with in the spirit of the joke would be RD saying she was “slicking off” when she meant “slacking off”.

@Brass Beau  
The problem with translating this is that the English equivalent to nakaore would be something like “couldn’t get it up” or “Going limp-dicked”, neither of which would be reasonable for RD to mistake for “slacking off”. This really is a case where being “correct” in the translation would lead to a bad localization.
 
Like, if RD said something like “I was a total limp dick and couldn’t finish,” you’d be preserving the meaning of the original joke, but then nothing after that would work, since that would require her to understand what “limp dick” means. Changing it to a malapropism spoils that first line a bit, but lets the rest of the joke function.
 
It’s not an ideal way of doing it, but sometimes translation requires stuff like this.

@A Non Man  
Thank you random moon creature.
 
Up high!

So, this here is what you can call a tricky translation problem. It depends on punnish wordplay, with RD mistaking one word (nakaore, which is literally to fold in the middle, but as was pointed out has the slang meaning of going soft during sex) with nakadarumi, which means to slack off. The only way to make a translation work is to slightly change the joke for the translation.
 
My solution would be to render it this way:
 
Panel 1
 
RD: Aw, man. I tried really hard yesterday, but I ended up jerking off. I couldn’t make it all the way through.
 
Panel 2
 
RD: Um, I got lazy while I was doing my homework and only got half of it done. Why?
 
Wait, you mean that’s called “slacking off”? So, what’s “jerking off” mean, then?
 
Panel 3
 
RD: HUH?!
 
Uh, I, um… I had no idea that’s what that meant…

Just when I need a translation Luna can’t be found.

This is what I got with google translate:  
—––  
—––  
No ~ I did my best yesterday, but it broke off ~.  
—––  
I couldn’t do it until the end.  
—––  
Well, it’s full of homework and only half of my homework is progressing …  
—––  
Is it “slack”? Then what is “folding”?  
—––  
Yeah !!  
—––  
Ah … I don’t know that … Such …  

@RAMMSTEIN45
 
Best guess using Google Translate. Minor lewd warning.
 
So~ yesterday  
I did my best  
but went soft during intercourse (中折れ)  
I tried~
 
In the end, I couldn’t finish. You know?
 
So I have a lot of homework and still only half of it done.
 
Oh, it’s “中だるみ” (slacked off)?  
Then what is “中折れ” (went soft during intercourse)?
 
Oh no!
 
Er … should I say  
I don’t know…  
It’s …

Someone has to sign the petition and maybe we’ll see more of human rainbow dash making a fool of herself. https://www.change.org/p/hasbro-save-equestria-girls-digital-series

Can someone translate the MoonRunes please?

I don’t know what’s going on either, but why is Dash so cute ?

I wonder what is going on.