鬼のパンツは いいパンツ
つよいぞ つよいぞ
トラの毛皮で できている
つよいぞ つよいぞ
5年はいても やぶれない
つよいぞ つよいぞ
10年はいても やぶれない
つよいぞ つよいぞ(注1)
はこう はこう 鬼のパンツ
はこう はこう 鬼のパンツ
あなたも あなたも あなたも あなたも(注2)
みんなではこう 鬼のパンツ

This is pretty funny! http://www.youtube.com/watch?v=5zmg7dlf3sQ

My translation:
Ogre undies are good undies.
They are strong. They are strong!
They are made from a tiger’s pelt.
They are strong. They are strong!
Even worn for five years, they don’t rip.
They are strong. They are strong!
Even worn for ten years, the don’t rip.
They are strong. They are strong!
Let’s wear Let’s wear Ogre underwear
Let’s wear Let’s wear Ogre underwear
You too, you too, you too, you too
Let’s all wear Ogre underwear

Setsubun is Feb. 3!