A derogatory term referring to a Chinese person. The referrence is made because the face is preportionately flat, and thus the Chinese person potentially possesses the ability to literaly bite a wall.
Bad Asian Driver: *Cuts you off*
You: "Damn wall biter! Learn how to drive!"
To be fucked in the ass so hard without lube (either literally or figuratively) that you are never the same again.
"After giving his brother a Morning Wake-up Call, he was completely Wallstered when his brother retaliated by pouring a gallon of sac soup on him while he was tossing the dwarf to some kids program on tv.