Hey man! Sorry it took so long for me to respond, been doing holiday family stuff
! You are right, most peeps get flowers, vines, or fairies behind the ear but most anything can be done there. Sensitive area tbh but even tribal designs can be worked to shape the contours behind the ear and neck. Beyond that, I've seen native american feathers, bear claws, pet paw prints, religious symbols like cross's, and even script and stars done behind ears.