I have to say, I am laughing so hard right now. You've captured Rainbow Dash's personality perfectly. She's cocky, arrogant, and can be a pain to be around. Twilight's being herself, a great friend. This does a brilliant job at reminding us of Rainbow Dash's ever-growing need for attention. It also shows Twilight's amazing amount of willpower. After a stunt like that, most ponies would have either given RD a nice blow to the stomach or walked away. This comic is brilliantly made, but I can't quite say it's the most original. It has the overall feeling of the "Ripped Pants" SpongeBob episode, where SpongeBob pretends to drown in order to get attention. I love this comic. I hope to see more of your work soon.
So is standard for me, I'm going to start off my saying that while my rating in terms of stars try to be fair, know it's rather incongruent with art. I think trying to put a numerical rating on something is superfluous, but since I have too, I did my best to give an accurate rating. Now, onto the critique!
First things that hits me is where I'm sure the idea was heavily inspired from the episode "Ripped Pants" from the show Spongebob Squarepants. However, this comic does a great job of making the joke fit without seeming like it's ripping everything off from that episode.
The first things it gets right is pacing. That sudden rush before it suddenly dies down leave the reader somewhat on edge. It helps draw the feeling out, making it feel stronger and stronger before suddenly get cut short in a swift and strong manner. That sudden change of mood allows a quick 180 so fast you can't help but laugh at it.
The last 3 panels help drive home the joke. Some of us have that friend who has faked something serious for a laugh, so having Twilight's reaction lets the reader relate on the other side. The last 3 panels are also very well paces. We have the frame where Twilight realizes what happens. The next one, you can see her annoyances, with the well place juxtaposition of Rainbow Dash in her still ecstatic face creating a sense of 'conflict' that you can't help but chuckle at.
So, what is my final verdict? Well, the images are well drawn, the joke is well paced and draws from a source without ripping it off outright. All in all, I give it high regards. Good job.