1)I know a bear that you don't know
  Yogi, Yogi
  I Know a bear that you don't know
  Yogi, Yogi Bear.
  Yogi, Yogi Bear,
  Yogi, Yogi Bear.
  I know a bear that you don't know,
  Yogi, Yogi Bear.

2)Yogi's got a little friend,
  Boo Boo, Boo Boo

3)Yogi like's it in the fridge,
  Polar, Polar

4)Yogi takes it up the arse
  Brown Bear, Brown Bear

5)Yogi uses Featherlite
  Care Bear, Care Bear

6)Yogi's got a cheesey knob
  Camem, Camem

7)Yogi's gone is long and green,
  Cucum, Cucum.

8)Yogi does it all night long
  Threadbare, threadbear

9)I would shag it all night long
  Dani, Dani

10)Yogi likes it nice and rough
   Grizzly, Grizzly

11)Yogi takes it up the chimney
   Sooty, Sooty

12)Yogi does it up in trees
   Koala, Koala

13)Yogi wears womens' underwear
   Teddy, Teddy

Plus any other clever bear jokes anyone can think up, 
in the same format.

If you aren't British you may not get some of these jokes.
Just take it as read that we think they're funny. More so when
Pished.