Possible Clues:

• Long and sinuous
• Thin and slippery
• Long, slippery and sinuous
• Long and twisty
• Want to be topless and slippery
• Point to butcher briefly close to bridge going round Serpentine
• Hard to grasp
• Difficult to catch oriental assassin who's lost tail -- and he's back on the turn
• Hard to get a grip on
• Part of 'iking shoe close to bank in position that's windy?