look up any word, like the eiffel tower:
 
1.
The indentation in the back of the neck at the base of the skull, especially when pressed upon by a small child's thumb.
Etymology: mwde up by my younger brother as a toddler.
"Prestush, prestush, prestush," my brother sang, as he pressed his thumb into the indentation at the base of my skull. "Prestush, prestush, prestush."
by Paul F. Walters June 17, 2005