suck suck suck daddy joe ur mom would typically use this when doing joe (ur dad)
That is how it could be used in a fashion sense "ur mom".
The finest person you'd ever see
Brad: Dang, ur mom is looking good!
Ur mom is just a potential come back for any possible thing say like for example
Person 1| Why are you so lazy?!
Person 2| ur mom
Luke|how are you?!
Brooke| ur mom
Aliah g|Why don’t you work out
Me(Brooke)| ur mom
Like aliah If You see this I Would like to say that your ugly and need a life<3
ur mom- a common comeback for when anyone says something to you