When you want to show off in a sushi restaurant as THE connoisseur, you can of course order an omakase course and let the sushi chef, the Itamae-san, serve you the best delicacies he has been able to find at Tsukiji that day.
That may however be dangerous for your wallet. Sushi chefs have a rather obscure way of setting prices and omakases are always expensive.
Luckily, there is another way to boast your way to sushi stardom: use the special sushi shop slang to demonstrate you know your way around.
Here are a few examples of "itamae-nese":
otemoto - chopsticks, normal would be ohashi. "Otemoto" means literally "at the base of your hands."
murasaki - soy sauce, normal would be shoyu. Murasaki means "purple" and so refers to the color of the sauce.
agari - tea, normally ocha.
gari - thinly sliced ginger pickled in vinegar. "gari-gari ni yaseta" means "rattlebones," but I am not sure that is related!
ichinin-mae - a serving for one person, usually referring to the thick, sweet omelet eaten at the end of the course. Literally, "in front of one person."
odori-ebi, "dancing shrimp," a shrimp that is still alive.
hikari-mono, "shiny things," fish with the skin still attached as aji, horse mackerel.
shari, vinegared sushi rice. This is my favorite one: cooked rice normally is gohan. Shari refers to the Buddha's ashes, which were considered an important relic in Buddhism. When people are cremated in Japan, the body is not wholly reduced to ashes, but brittle bones are left. Small pieces of bone resemble rice grains, as they are white and shiny. The term is not meant to be unpleasant, but rather an honorific. In fact, as very few pieces of Buddha bones made it all the way to Japan, in medieval reliquaries often grains of rice were used as a substitute!