The phrase "glass backs" refers to individuals or groups who appear fragile or sensitive, like glass, and are easily hurt or offended.
Sentences with «glass backs»
It comes with glass back body with metal frame. (phoneradar.com)
This means sound isn't as distorted when played through the rear speaker, plus it stops the shiny glass back of the Nexus 4 scratching on the surface it's sitting on. (techradar.com)
It comes in a unibody design, with 3D glass back on both front and back. (indianexpress.com)