Chaucer uses a slightly mocking tone to describe the Summoner in the General Prologue of The Canterbury Tales. He first describes the Summoner as having a "cherubynnes face" but quickly goes on to say that the same face is covered with acne, which is why it resembles the stereotypical red-faced cherub (GP line 626). Chaucer describes the Summoner's pimpled face awhile longer before describing his terrible breath. Chaucer also mentions that he's a drunkard, and at this point it becomes clear that the narrator doesn't much like the Summoner.
Chaucer continues to mock the Summoner when describing his role in the church: "A better felawa sholde men noght fynde, he wolde suffre, for a quart of wyn, a good felawe to have his concubyne, a twelf-monthe, and excuse hym atte fulle" (lines 650-654). Rather than extracting money from the population for atonement of sin or Church fines, the Summoner deals in wine, concubines, and monetary bribes. Chaucer uses the same mocking tone to describe many of the pilgrims, as many of them are corrupt and are on the pilgrimage for selfish reasons.