The act of checking out ones own ass to make sure it is appealing. This can also include another persons opinion to back up your own.
Usually played out by a female who is looking to purchase a new pair of pants or the like, and this act will either make or break the purchase.
(Carly was trying on a pair of pants at the mall, and when she exited the change room to show Megan there was a moment of awkward silence.)
Carly: Wow these jeans fit like a glove, and they're so comfortable!
Megan: uhh.. Carly, have you given yourself the booty assessment yet?
Carly: ...no? (walks to the 3-way mirror and does a twirl)
Carly: Jesus christ are you kidding me? These pants make my ass look as deformed as Joan Rivers' face!