little johnny sees his mother walk out of the shower and sees her vagina
he asks her what is it , and she is embarrassed and replies , oh thats mommy blank sponge.

a few days later johnny spills a glass of milk on the floor , mommy i need your black sponge to mop up the milk.

she replied i lost it honey

a couple of days later he came running up to her and says mommy i found your black sponge , mystified she says where honey

little johnny says , its over at mrs johnsons house and daddy is washing his face in it

I don't get it??? must be a canadian thing