Like a rosebush
(Other definitions for prickly that I've seen before include "Like a hedgehog - easily offended" , "Thorny, bristly" .)
(Other definitions for thorny that I've seen before include "(Of problem) causing difficulty; prickly" , "Not easy" , "Problematic (question)" , "Spiny - difficult and controversial" , "Troublesome or difficult, like briars?" .)