Humbert describes Gaston Godin, a well-respected though truly unimpressive French professor who seems thoroughly uninterested in Humbert's relationship to Lolita. Based upon Humbert's description, Gaston seems to have his own bizarre tastes (which run toward young boys), so the two just enjoy each other's company and keep their private lives, well, private.
They often play chess together in the Humbert home.
Humbert reveals that Gaston later became embroiled in a nasty business in Naples, Italy.
Despite his mediocrity and lack of inspiration, Gaston is a decent companion and something of a distraction and alibi.