The only real comeback to ya mum that isn't whining about how infantile your insulter is. We can only assume what is meant by 'this'.
Scenario 1-boring, slightly civilised
Tony: What are you doing tonight?
Gordon: ya mum!
Tony: Now do we really have to resort to this childishness?
Gordon: Does ya mum have to resort to childishness?
Scenario 2- Childish, good
Tony: What are you doing tonight?
Gordon: ya mum!
Tony: keep my mum out of this and I'll keep this out of ya mum
Gordon: Yes, master.
Tony: What are you doing tonight?
Gordon: ya mum!
Tony: Now do we really have to resort to this childishness?
Gordon: Does ya mum have to resort to childishness?
Scenario 2- Childish, good
Tony: What are you doing tonight?
Gordon: ya mum!
Tony: keep my mum out of this and I'll keep this out of ya mum
Gordon: Yes, master.
by kung-fu jesus October 30, 2004

The most important year in British history. After the death of Edward the confessor, three aristocracy of europe claimed the throne. Harold II had already taken the throne. His first opposition came from Viking warlord Harald Hadraada. The viking army was defeated without much hassle. William, duke of Normandy then came from France to the south coast. Harold II ploughed his army onto William's without rest. They made good time, but were exhausted. William used simple but effective maneuveres to kill off many thousands of English. Harold died during the battle, and William became William the conquerer. All monarchs since have been of his lineage. Also, there have been over 50 attempts to invade britain since that point, all of which have failed.
by Kung-Fu Jesus April 25, 2004

Used sexually, the genitalia of a prospective sexual partner. Either vagina (pussy) or penis (snake).
Ah, the other white meat...
by Kung-Fu Jesus April 21, 2004

You got the origin wrong. The phrase has been a part of british culture since the 19th century. There are recorded uses of it since at least the 1880's
by Kung-Fu Jesus June 14, 2004

For something (usually not a physical object) to be brought up; usually in conversation or the acts of a superior.
by Kung-Fu Jesus April 14, 2004

by Kung-Fu Jesus May 9, 2004

(adj.) Any form of killing where-by the killer will stand square-on to the victim while stabbing/shooting them in the lower chest region (although it could also be in the face, neck, legs). Usually, this is done with excessive force.
by Kung-Fu Jesus May 5, 2004
