I only knew about the book cos of the movie starring Mae Whitman (aka Ann aka Egg)
The plot is really main character Bianca is out with her friends at some teen club when the school's player-in-residence starts a conversation with Bianca so her hot friends will see he's giving their friend attention and thus, want to have sex with him. Wesley informs Bianca of her position as a DUFF, Bianca throws a drink at him, and here we have the opening.
But the fact is, while her friends are actually her friends and treat her as such, Bianca can't get Wesley's words out of her mind. Couple this with Bianca's absent mother and on-the-brink-of-relapse alcoholic father, Bianca is hurt and looking for escape. Which she finds in boning Wesley cos why not screw (one of) the thing(s) making you upset?
The book is surprisingly non-judgemental about all the sex. I mean, the character are at times pretty judgemental, though there is growth, learning about slut shaming and how maybe that's a terrible thing and knock that off.
There are teens making mistakes, as teens are wont to do. There are hurt feelings and drama, though overall the book is very funny. Of course Bianca, being the DUFF and therefore opposite of her hot friends, is super smart and sarcastic. There are realizations and growth and moments that were surprisingly touching.
As I said in the beginning, the book was light and fun and a quick read and the right thing at the right time.
Keplinger, Kody. The DUFF. Poppy, 2010.