Made wildly popular in Japanese Animation. Where there is more then three men, that gather around one central, female character
(As seen in: Ouran Highschool Host Club, Hana-Kimi, Fruits Basket ,Fushigi Yuugi,Saint Seiya,Wallflower.)
"Oh, just my reverse harem."
"No, shit. How do I get one?"
The male version of this is harem