Deine Mutter
"Deine Mutter"-jokes are often used among German teenagers. You can use them to insult someone (or his/her mother).

Otherwise you can use "Deine Mutter!" -> "deine mudda!" (pronounce it die-ne mu-dah) as a slang for "shove it" or when you want to deny sth.

And you can compare it with "your mum".
As an insult:

- "Deine Mutter steht vor KiK und schreit "Nur ich bin billiger!"."
(Your mother stands in front of KiK (that's a cheap boutique, where nobody wants to buy his/her clothes) and shouts "Only I am cheaper!" (cheaper in the meaning of slutty))

And as "shove it":

- "Bring doch den Müll runter"
(Carry off the trash)
- "Ey, deine Mudda!"
(Your mum!)