The concept of "stomach" can be expressed by simply patting your stomach twice.
Or use fingertips of a "bent-B" hand to poke it twice.


Or you can point to it.

Remember "signs" are not English words.
If you have a sentence like "I can't stomach the sight of blood" you should
use a sign that represents the concept. For example "tolerate"
(a version of the sign PATIENT) would be a good choice.
If you are in a doctor's office and need to describe the stomach in more
detail you can use "classifiers"
to describe the size, shape, and location of the stomach.


You can learn
American
Sign
Language (ASL) online at American Sign Language University ™
ASL resources by Lifeprint.com © Dr. William Vicars