To sign sick, make a face that conveys illness, and point to your forehead with your dominant hand and to your tummy with your non-dominant hand. Use the middle finger of each open hand with fingers splayed out, when you point to your forehead and tummy at the same time.
Our babies will feel more empowered if they are able to communicate suffering. Teach your baby the sign for sick, along with other emotion and sensation signs that will help ease their anxiety once they are able to communicate such feelings with you.
Hopefully we won’t have to use the sign for sick often, but it is a good one to add to your list of important baby signs.