THICK-PIZZA: Deep Dish
There are quite a few ways to sign PIZZA. Do one of them and then sign THICK.
In my example (below) I'm spelling "pizza" using a lexicalized form that overlaps the letters (note the second frame where the "P" and the "I" are both visible at the same time) and uses the "double-Z" (based on a "V" hand moving in a "Z" pattern).
Then I use "C" handshapes to show how thick I want my pizza. Okay, sure, I'm hamming it up a bit here (because pizza gets me excited) but in ASL you've got to get used to using your face or your stories will be boring.
