@Marnssj  
Can you help me explain which butt check of Rainbow Dash’s you’re referring to? I know Tetrominon said it was her left cheek but I can’t tell which left it is. The left from our view or her left?
 
@Psycho333  
Dashie still has an awesome butt. ;)
 
@Zeyon  
I’ve studied the show’s art to make these and I understand what you’re getting at. The thing is, I’m training myself to eventually start drawing clop pics and I wanted to make the Mane Six’s butts bigger than how they usually look.  
As for Rarity’s lack of an ass crack, I’ve been trying to make variety of the ass shots I keep seeing through different drawing views and some of them don’t give the pony a butt crack. I can fix this however if you want and I can make sure that everyone will have an ass crack from here on out. ;)
 
@Kamazeustra  
Yeah, labeling the pics even though they’re completely obvious is just a thing with me.
 
@Da5ch  
Thank you very much! You won’t believe how happy I am to see myself actually get positive reception on Derpibooru!

Oh man, look at that high score! You’re really improving there, Red. It’s far from perfect (the proportions are still way off on some of them) but I’ll be damned if that isn’t the cleanest lineart I’ve ever seen you do, and excellent use of the cutie mark vectors too.
 
You are really improving, keep it up.

Good thing these were labeled.

Constructive Criticism? Aw… well… how about this. The straight on butt shots (Pinkie/Rarity/Twilight)kind of make their hips look wider than the rest of their bodies, if you look at in the show (and actual horses) their legs line up with their barrel and so their rear width would line up closer with the body. I know that they are humanized ponies and their butts being possibly wider may occur, but I don’t know I thought I’d throw out the idea. Twilight is probably closest to a narrow enough profile. I also wonder why Rarity doesn’t have a butt crack like Pinkie or Twilight in that view?

@Marnssj
 
Despite the error Dashie’s butt is the best butt

@Red-Supernova  
Rainbow Dash’s cheek extends way too far out for proportion. The picture with Fluttershy’s butt is from a similar angle and I feel just looks much better, but I feel like the error with RD is more of an oversight than anything.

@ArkyNoid  
Personally, I see these photos as lewd pictures that were taken by a mysterious photographer while the Mane Six were distracted. But hey, maybe the Mane Six agreed to let someone take pictures of their bums out of politeness.  
Whatever purpose these photos were taken for, its usually up to the viewer’s interpretation. And the Mane Six aren’t the only ones who have had pictures of their butts taken with or without their permission. ;)
 
@Tetrominon  
How is it out of proportion? I’m willing to improve so I’m all ears for hearing how.  
One of my reasons for how it looks out of proportion though is that out of all of the Mane Six’s butts, Rainbow’s is more firm and perky due to her being an athlete.

@Foric  
No, I thought of that, but it’s still way too big to match.

@Tetrominon  
angle bro!

Dash’s left cheek is WAY out of proportion with the other one. Never mind flying, I’d think she’d have a hard time standing like that…

Most wanted butt bulletin? hehehe