Possible Clues:

• He performs feats that will hold water
• Drinking glass or old acrobat
• Glass - acrobat!
• Taking a drink, one may go head-over-heels!
• Acrobat demands drinking vessel
• A glass; part of lock
• Vessel; flipping performer?
• Vessel in lock: it must be moved to open gate
• Acrobat that can clearly hold a drink
• Glass slipper may become this