A bean, or "The Bean," is a word or phrase used to describe the shape of someone's head. Typically, someone with a long or irregularly shaped bald head. This expression is frequently used to describe someone who has had a clean-shaven haircut. Or to refer to bald persons in general.
Being a bean is not only a term used to describe someone being a dick or asshole, it's also a lifestyle. Being a bean means a lot of things, for example "Ronan" says that he is going to hang out with his friends but, he decides to be a BEAN and stay inside. Being a bean is something you don't want to be, as it makes you well, a bean. Bean can also be used in the sense of being "beany" where someone is acting like a bean making them beany.
Person 1: Are you coming gym after school?
Person 2: Nah bro I have to wait for the new Carti drop.
Person 1: Don't be a bean man!