"Welcome Friends to Canada" is a song sung by the Canadians in the Season Seven episode, "It's Christmas in Canada". The song is sung en masse to welcome the boys to Canada.
Background
When Tuong Lu Kim City Airlines plane crashes in Canada, the Canadians are afraid it's an invasion. When Kyle Broflovski assures them it is not an invasion and he just wants to speak to the Prime Minister and get his his brother back they rejoice and sing a welcoming song.
Lyrics
Welcome friends to Canada! Canada Friends loves you!
We're just like any other country without the big ta do!
Sailor:
We greet thee with pleasure, but one question, if we may?
Man in Suit:
What brings you folks to Canada? Why are you here today?
His brother's here some where. The question is, is where? You must talk to the new Prime Minister if you think his brother's home's back there.