This is a easy costume for your dog. :) I noticed there were a couple of nigiri sushi costumes out there, but had never seen one that was a maki roll so I decided to try making one myself.
Step 1: Sushi Roll Dog Costume
First you will need your supplies:
Sherpa Fleece (I have a medium dog so I used 1 yard)
Fabric (I like the backside of faux seude because the shiny side looked right to imitate seaweed)
Thick elastic (I also got 1 yard of this)
Velcro (I use the iron-on kind)