Possible Clues:

• Once this twice shy
• What's to be done with 1across? The answer is part of the X, perhaps
• 'Once ......, twice shy'
• Once this shy and shy, perhaps
• Something heavy might be hanging around here
• Once the first part got tenmore
• 'Once ...... twice shy'
• With your teeth you bent this around it
• 'Once . . . . twice shy'
• Not the whole of X in the mouth