A double meaning, where on the one hand it refers to a male who has a rather large penis. On the other hand, it refers to a heterosexual male who is acting in the perceived manner of a gay male, as sort of a warning.
More of a nickname than anything, of which there are hundreds of terms, some limited in popularity.
When used in regards to one's behaviour, it is usually said in a warning note, or tone, sort of as more of a rebuke, than anything else.
Implies unacceptable behaviour or mannerism, making it a derogatory remark.