Tongue rolling is the ability to roll the lateral edges of the tongue upwards into a tube. The tongue’s intrinsic muscles allow some people to form their tongues into specific shapes. Rolling the tongue into a tube shape is often described as a dominant trait with simple Mendelian inheritance, and it is commonly referenced in introductory and genetic biology courses, although there is some disagreement.[1]
https://en.wikipedia.org/wiki/Tongue_rolling
https://upload.wikimedia.org/wikipedia/commons/a/a0/Tongue_rolled.jpg