None exists in western culture, matriarchal societies being rare. If one does exist, it may be in the Mosuo language. Although, the Mosuo (or Na) culture tends toward serial monogomy, so even they may not have a word for "male concubine" (a bit of an oxymoron).
In English there are no masculine or feminine forms. English uses gender specific nouns for a male or a female. The word concubine is a gender specific noun for a woman; a word for woman who lives with a man but has lower status than his wife or wives. There is no equivalent noun to apply to a male except perhaps a slave.
"The Concubine's Children" was created in 1994 by Denise Chong.
The Russian Concubine was created in 2007.
The Concubine - novel - was created in 1966.
Fragrant Concubine was born in 1734.
The Magnificent Concubine was created in 1962.
The Concubine's Secret was created in 2009.
Fragrant Concubine died in 1788.
Concubine Qi died in -194.
The Russian Concubine has 517 pages.
The Concubine - novel - has 216 pages.