Freddy licks his lips, enjoying the boy's fear a moment before he speaks. Commas usually function within sentences to separate elements. I'm going to give you some pointers. Remember, of course, that failing this course is deadly. He smiles again, then picks up the lecture.
Commas are used:
To separate independent clauses linked by a coordinating conjunction (for, and, or, so, but, nor, yet). Freddy is a misunderstood soul, yet he is always portrayed as a monster who gets it in the end in all his fuckin' movies.
To set off most introductory elements. An introductory element modifies a word or words in the main (independent) clause that follows. Unfortunately, we never see Freddy win in his movies. The only Freddy can win is for his lovely piggies on the fan fiction sites to write it in, and even then it means whippin' that punk bitch Jason Voorhee's ass.
To set off non-restrictive elements. Huh? Jamie struggles to understand while Freddy controls his anger at the boy's ignorance. "Commas around part of a sentence often signal that the element is not essential to the meaning of the sentence. This non-restrictive element may modify or rename the word it refers to, but it does not limit the word to a particular individual or group." He smiles expansively, then offers an example of a sentence with non-restrictive elements: Freddy, who has killed many children, would like nothing more than to wipe out Springwood's child population before moving on. The middle part's non-restrictive. By contrast, a restrictive element does limit the word it refers to: the element cannot be omitted without leaving the meaning too general. Because it is essential, a restrictive element is not set off with commas. The Dream Deamon who kills bad little piggies likes to thin out Springwood's population.
To separate items in a series. Freddy loves his leather glove with knives, his fedora hat, and kiling kids while they're still virgins. Because it's funny knowing the last thought to run through their pitiful little minds is now they'll never get laid. Freddy finds this hilariously funny for some reason, perhaps because that's exactly what ran through Jamie's mind at the Dream Deamon's words. The laughter subsides and once more Freddy speaks.
To separate coordinate adjectives. Freddy is a mean, cold mutha fucker.