I am taking a wild guess here, but to this reader's opinion the characters in Axel seem to establish their "manliness, sexiness and overall coolness" by using fuck as often as possible in their dialogues. Like twice or three times per sentence sometimes. I am not particular squeamish were swear language is concerned, "hell" I use it myself, but there is such a thing as too much, especially when I start rephrasing and -writing certain passages.
Aside from the use of too many "fucks" the story was quite entertaining, though I could have wished for a sooner reconciliation of Axel and Izzy, as their separation is more of less based on some machinations by the very obvious villainous foster mother of Axel. Some mature sitting down and talking about the things that don't add up and less immature behaviour would have done a world of good.
Despite my quibbles I nevertheless enjoyed the novel quite a lot so I still grade it with a C+.