What does this mean?

[JoeDoman]

If a girl calls her mate big gums what does it mean?

[eddie18]

maybe its big ums.. like big boobs as in Married with Children.. maybe its a girl thing

[2nd row]

     a ' girlie thing/saying ' ..... one with big gums , has a big mouth, always gossiping, giving away/telling  to other people, what is supposed to be a very good secret between two friends, always talking, sometimes without thinking first,   " what you tell 'im that for "? " you went an' told my mum about friday night....." " what you tell my dad for that i found that 20 quid note ? etc.etc.etc.......... big gums......