Clarence is wearing a t-shirt. (I don't know if) he was out in the sun all day at the concert. Since he was out in the sun all day he got a sun burn on the back of his neck because he forgot to apply sunscreen there. He now has a red neck.
If a smaller controllable fire is started in front of a bigger fire, then you can deprive the main fire of it's fuel. The website, How Stuff Works has a bigger explanation.
