"Hal points to the lump of Kodiak in his cheek"
Chewing tobacco
Public DomainChewing tobacco

 Kodiak is a brand of chewing tobacco produced by the American Snuff Company. They produce three different flavours: Straight, Mint and Wintergreen.

David Foster Wallace chewed tobacco for many years, and discusses the habit which he describes as "a vector of self-contempt" in this excellent interview with The Believer.