Human engraving

Human engraving is a term used to talk about self harm in a non explicit way

Arnault : I’m a real human engraving adept !
Here Arnault is in depression and suicidal

eating a bag of teeth

Used to describe an repulsive, purposeless and ungrateful activity

The idea behind this expression is that eating a bag of teeth would erode both teeth as they have are equally as hard

Damn! Working with this guy is like eating a bag of teeth!