I'm sure everyone has this problem in their classes. There is a kid in my Western Civ class who about every 5 minutes makes a snide comment that generally has no relevance to the topic of the lecture. He does so without ever raising his hand, and it is very disruptive to the class, which only has a precious 50 minutes to learn several chapters of material. Today he went so far as to let out a long and disgusting burp in the middle of the professor's lecture. I'm all for people asking questions about lectures, but how do I make this kid shut up without seeming rude in front of the professor?