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
Some stupid thing Middle School Xbox boys say
Like actually shut the fuck up ur 10 go play with legos or something ur mom isn't funny
ur mom refers as a comeback or a slur to some people. You may use "ur mom" as referring to your actual mom, or you may refer to "ur mom" as a sort of comeback when someone asks you something and you don't really know what else to say besides, "ur mom" lol hehe.
hey ur mom is over there!
hey what's up? ur mom hehe
yo, why are you so ugly? nah I'm not, but ur mom is..