Well, that would fall under the category of "slang". It is a mixture of "chilling" and relaxing... Which really is stupid, because both of those words pretty much mean the same thing! LOL!
If your face is moderately dirty a washrag will do just fine but when it is really dirty it need a warshing.
I didn't realize until I was an adult, that the proper term is washcloth!! I asked someone if they had any washrags, and they had no idea what I meant!