It’s like a doormat except your face is the thing being used. It’s usually a skater boy wiping his shoes on your face and it’s more popular with teenagers.
Person 1: I can’t believe that he used you as a facemat, his shoes are dirty, and he smeared the dirt all over your face!
Person 2: That’s what facemats are for, better than doormats.
Me: Thanks for asking, Juan. I was running super low on mental images of old girlfriends, coworkers and acquaintances to pud off to, so I logged onto Facebook and Facebeat literally all night long.