According to Urban Dictionary,

A Yoruba demon is typically a young man of Yoruba (the Yoruba is a tribe predominantly found in South West Nigeria ) descent who has the uncanny gift to effortlessly make ladies fall head over heels in love with him. He is naturally a gifted smooth talker and Casanova and prides himself in been able to acquire a huge followership of female admirers and side chicks. He is also gifted at absolving himself of any responsibility in his relationships. Generally, he is a seductive cock-tail of sweet and bitter.

Example:

There is no going back after you date a Yoruba demon, you keep coming back for more.