The set from CasaBento includes two shape imprinters, a crust cutter, a sandwich-edge-squisher (yes, the technical term) and a little scoop. Soft innards like PB&J, egg salad, etc.. work best. Horribly unhealthy Wonder Bread type breads work best, but Wonder Bread is too small. Here in Germany, they sell what they call "American Sandwich Bread" and it's pretty much Wonder Bread but bigger. I assume they must sell something similar in Japan, which is why it fits the cutter. It also helps to microwave the bread for about 15 seconds, then it accepts and holds the imprint much better and doesn't tear in the center when you squish down the edges.
You can make one big whole squished-edge sando or fold the bread in half and angle the cutter to make half squished-edge sandos. (I can feel my intelligence radiating out through this post. Can you feel it?)
Not microwaved long enough. Still cute.