Who is Eli LaCrosse from Ham on Rye and what is their importance?

From the outside, people would think that Eli and Henry are great friends.... always together. Henry, however, can't stand Eli and merely tolerates him. When Eli tells Henry he doesn't need to attend college orientation, Henry mistakenly listens to him. In response, Henry depants Baldy during gym class, exposing his pajamas, as well as his private parts.