すみません、まぐろアボカドを一つお願いします。 — Excuse me, one tuna avocado, please. (Kaiten · Sushi, Formal — to staff, JLPT N5)

Gesture & etiquette

Pointing to the item on the menu (if applicable), slight nod.

Many kaiten sushi restaurants use touch panels (tablet) for ordering. Check for a tablet before calling staff. Avoid yelling across the counter.