This is a common term used in China, specifically in hong kong or other canton populated areas. This literally translates in english to "F*ck your mother."
It is commonly used, when you are obligated to help someone, or you find someone's performance is below standard, or dissatisfaction.
This can also be expressed as," Diu lay lo mo ah!" Which is the same but with the "ah!", it expresses a deeper meaning/feeling.
Phonetical pronunciation: "Delay no more"
Jeff: hey man you got a dollar I can borrow?
Ed: Diu lay lo mo!
Jeff: dood, i always spot you with money!
Ed: Diu lay lo mo ah!