When using the bamboo mat I wrap it in plastic wrap and place it on top of a kitchen towel. The plastic wrap keeps the mat clean between rolls if things get messy. The towel will allow you to wrap and tighten while you roll. So start your initial roll and once you get a full wrap you can pull the front of the towel forward to add tension to the mat and the roll. Just be careful not to rill the towel too! The rice will adhere to the Nori and keep things together. Roll like a joint
pressure in the middle working outward. I leave about 3/4 of an inch towards the end free of ingredients so that the Nori will seal like the glue of an envelope.
When cutting dip the blade in water and wipe clean to prevent the guts from sticking and pulling out when you pull the blade through.
I like to make my wasabi from powder, then take a bit and smear a line from side to side so each bite will get a taste. I use Mirin since it is a touch sweet and generally tastes better than vinegar and sprinkle it liberally onto day old rice.