A few trends I've noticed...
The bush is making a comeback. Thank God!!!!
Girls work more on their asses now than ever before, which kind of pisses me off considering I've been an ass man since the 80's when basically the only chick's with asses were either black or Latina. In this sense I was born much too early. Better late than never I guess.
Porn has completely changed the game and now women think it's the norm to take it up the ass, so much so that they think you're gay if you're not down with the brown, which is extremely fucked in its own right.
Personally I've never really been into fucking girls in the ass. I've shared reasons why in the past which weren't pleasant, but honestly it doesn't even feel that great IMO. Basically a tight ring followed by the inside of a garden hose... I get the domination thing, but that can be achieved from pounding the sweet puss as far as I'm concerned.
There's going to be a ton of prolapsed anus's out there in the near future. Would be a great move if you're young and looking for a lucrative career to get into the proctology field.