Green’s Dictionary of Slang

sugar mummy n.

also sugar mammy
[on the model of sugar daddy n.]

1. an older woman who provides for the material wants of a younger male or female lover.

[UK]J. Braine Room at the Top (1959) 174: So far I’ve been unable to find one of the rich old sugar-mammies with whom, I’d been given to understand, the place abounded.
[UK]H. Davies Other Half 139: A sugar daddy or a sugar mummy’s all the same to me. When I was in Holloway there was this lesbian that everybody was scared of [etc.].
A. Livia Relatively Norma 105: [of a lesbian] You’re all set up with your sugar mummy and you don’t give one fuck about the rest of us.
G.A. Dunne Lesbian Perspectives on Work and Family Life 78: Being a woman’s ‘kept woman’ might even be seen as an attractive option and some lesbians I know have even made allusions to finding a ‘sugar-mummy’.
[UK]E. Tennant [title] Confessions of a Sugar Mummy.
[Aus]T. Spicer Good Girl Stripped Bare 129: ‘He’s looking for a “sugar mummy”. Women pay for sex then help their boyfriends emigrate to Australia’.

2. (S.Afr. township) a wealthy white woman who pays for the companionship of attractive, younger black men.

W. Gateria Black Gold of Chepkube 122: He said that the defendant, a young sailor from Japan had been unfortunate to get into the clutches of a sugar-mummy.
W. Mutahi World of Whispers 48: Mama Maria (for that is the name of the sugar mummy) might have sons the age of the young fellow.