How to get rid of rolls under butt? (photos)

This is best treated with liposuction.  This fat can be somewhat fibrous and is best treated with either ultrasound or laser assisted liposuction.

The roll or segment of fat under your buttocks was originally called the banana, and later gained the title of banana roll or banana peel.  The majority of authors describing treatment for this problem have approached the diagnosis of this problem as an unwanted collection of fat.  In point of fact, this is not an unwanted collection of fat but rather an unwanted membrane having similar anatomic characteristics to the infra gluteal fold.
When surgeons attempt to treat this fatty collection by liposuction alone, all they get for their efforts is a smaller version of the same problem.  In my opinion, the appropriate approach to rectifying the unaesthetic problem is to, along with minimal liposuction, fenestrate (make windows or holes in the membrane) which then relaxes and takes away the dent, and then the apparent fatty pocket disappears.
If you were my patient, I would use a blank canula inserted from two or three different directions to poke holes in the membrane along with liposuction which, in my experience, cures the problem.  In the alternative, since you are so young and in such good shape, a first pass at curing the problem might be the use of a blank canula by itself to destroy the membrane since it does not appear you have much excessive fat.