Okay:
Bonita- pretty (chica bonita...pretty girl)
Mamacita- It technically means little mama but men use it to women they think are sexy or beautiful (Hola, mamacita - Hello, sexy lady)
Negreita- Little black girl (Negreita es bonita...The little black girl is pretty)
All those words can be used in a flirty way... "Hola, mi negreita, mi mamacita ^.-"