You shouldn't discuss sex at work.
Brian is hanging in the break room with several of his coworkers on lunch.
Brian wants to entertain his coworkers with stories.
Brian talks about a good book he's been reading lately.
Brian talks about all the women he's been screwing lately.
Brian's coworkers think he's a man of culture, and ask him for other book recommendations.
Brian's coworkers find him crass and offensive, and a female colleague reports him to HR.