Any sushi-dunking-in-shoyu etiquette questions (i.e., should I dunk the rice or just the fish?) are easily resolved with Rakuten's sauce dispensing chopsticks. A set of two comes for $18 (w/o shipping) if you can sort through the hiragana and katakana on the Rakuten site. (via Ohgizmo!, Slashfood)

For a DIY set I suppose you could hunt down hollow chopsticks with tapered ends then insert eye-droppers on top. Or if you've got a cell biologist in the family, there are mini pipettes, in variable volumes and purty pastel colors. Then again, they might arouse suspiscions about iffy microbials. No sushi-san wants a B on the window.