Possible Clues:

• Shock social event that Tom might bring up?
• The air in this particular ice cream; it's all the cat's problem!
• Cat's stomached musical delivery?
• One might make a Persian gag?
• Musical dance which is in the middle of Cats?
• Cat's bane
• Uncomfortable thing in a cat's stomach?
• Henry and Brian briefly returning a couple of pounds that Tom's coughed up?
• It's hard for queen to stomach this dance at end of hippy musical
• Downside of some self-cleaning