A clever combination of "that's what she said" and "your mom!". It was created to avoid the argument that "that's what she said" creates confusion because "she" is nobody while adding the punch of "your mom" jokes to it.
The phrase "last night" may be added to the end if extra pwnage is needed.
Person 1: "Whoa, that's a big hot dog"
Person 2: "That's what your mom said!"
Person 1: "Whoa, that's a big hot dog"
Person 2: "That's what your mom said last night!"
Yeet your mom means that you yeet your mom out of the window if shes annoying.
Yeet your mom
Mom: Are you done with your homework?
me: No! I´m playing minecraft!
Mom: Make your homework now!
Me: You are annoying......
*me yeet my mom through the window