bang nanny 

A woman that a man gets into a relationship with primarily so she'll watch his kids from another relationship

Her: "Sorry, we have to cancel girls night. I forgot that Boyfriend has custody of his kids tonight and so I have to make them dinner, help them with their homework, and prepare their school lunch for tomorrow."

Friend: "Girl, he's using you as a bang nanny! DTMFA."

bang nanny by Mai Ainsel October 21, 2019