Cetacean Frottage.

[swestrup]

Now it can be told: Narwhals are a rare and ellusive breed of whales in which the males all have a long horn-like tooth projecting forward. Recent studies have discovered that the tooth is completely covered in nerve endings, making it one of the most sensitive teeth ever discovered. So, its hard, its long, only males have them, and Narwhal males like to rub their horns together. Nuff said.