Great story, However I noticed a few minor recurring issues.

“Look, I know you’re upset that you don’t have anypony special to spend time with Flitter, but do you really have to take it out on me?”
Flitter glanced away from her sister, uncomfortable with how Cloudchaser was looking at her. “Well sorry for not being pretty enough to attract somepony…”

Each time someone speaks, you need to make a new paragraph.

“Good.” He simply said with a smile, leaving his brother and Flitter alone as the couple headed out to enjoy their vacation. Finally, Flitter and Rumble were all alone, alone for an entire week.

“It’s a couple of hours away from lunch, so what do you want to do in the mean time?” Flitter asked the young colt of whom she was now responsible for.

>alone, alone for an entire week.
Repetitive.
Stahp.
Also, we already know that Flitter is taking care of him. You don't need to tell us that.

Minor things like that, you should get an editor if you don't have one already.

I'm hooked
1-media-cdn.foolz.us/ffuuka/board/wsg/image/1349/15/1349156948592.gif

>everytime he as alone in the house
"every time" is two words, and I think you meant "was", not "as"

>Rumble began to dominate Flitter right away
d24w6bsrhbeh9d.cloudfront.net/photo/2306687_700b.jpg

You missed a few commas, too

oh. my.

ARE THEY HUMANS OR PONIES?

You had me, up until you made a COD reference. Oh well, i guess i'll keep reading.

kinky.make moar

In some of his fantasies, Rumble would dream of sticking his hand down the backside of Flitter’s pants

sticking his hand

his hand

THE FUCK???!!!!?!?!

Its anthro ponies people

NOOOOOOOOO
your cover has been blown agent rumble!
ABORT! ABORT!

I think you misunderstand what Anthropology means.
-The Study of Humanity

Less confusion if you used Humanized, because even with Anthropomorphic it brings to mind humanoid ponies.

1416674 anthro

1453447 antrho

dirtydozenclub.com/wp-content/uploads/2012/01/please-sir-can-i-have-some-moar.jpg

“You’ve been a naughty colt, haven’t you Rumble?”

nhl.com/features/gallery/finals/gm3/images/page3.jpg
Oh shit

I can't stress this enough but please look up 'anthropomorphic' in a dictionary. As they appear in the show the ponies are already anthropomorphic, the word you are looking for is bipedal. Only in furry slang does anthro mean bipedal and thanks to that whole generations of furfags are doing it wrong. Let's not follow in their footsteps please?

media.tumblr.com/tumblr_m8e2mkB1Ox1qhh48w.gif

And that's all I have to say about this....

1453447

That made me lol so hard.

I need an update to this please.

Rumble shook his head, trying to rid himself of such thoughts, but it was no use. He may be young, but he wasn’t stupid… in some ways. As much as it hurt to admit, he knew that he was only chasing after a fairy tale. There would be no way that Flitter would be attracted to him, so if she wasn’t going to accept his love, then what she didn’t know wouldn’t hurt her, right?

Yo there's a club it's called every one in high school every dam girl there is a god dam tease not shitting you take a look at this middle school called Cairo when ever any one goes to mt pleasant south Carolina

2331606 WTF does that even mean!?!

FUCK

Code Red. Rumble's been caught. *starts freaking out Twilight style.