Kobashira is trough shell scallops. Generally, they are already removed from the shell, and only the adbuctor mucle is eaten.
For nigiri sushi, wrap a large strip of nori that covers the sides of the rice ball and protrudes around the top to form a cup (the nori should be 1 by 7 inches). Fill the formed cup with a spoonful of kobashira, careful not to let it spill over. Serve immediately as the nori will wilt and turn soggy.