so ashamed one wants to disappear; wanting to sink into the ground in shame
Idiomatic expression used when feeling extremely embarrassed or ashamed, as if one wishes a hole would open up to hide in. Often used in the form 穴があったら入りたい気分 or similar.
I tripped in front of everyone and felt so embarrassed I wanted to disappear.
After making a mistake like that, I'm so ashamed I could just sink into the ground.