@KrautalicornSS
Not typically. They usually have just a rear flap (if they have a flap at all, mine don’t) and they usually zip up the front. Pinkie’s doesn’t appear to have a rear flap. Dashie’s zips up the back instead of the front, which means she probably needed somepony to zip her up when she put it on.
Twily likes what she sees, can’t stop staring. I bet if there weren’t all of her other friends and she was alone with rainbow dash, she would do things to that exposed rear now…