Possible Clues:

• One is positive that the bitch has a twitch
• Positively bitchy she is
• Overbearing tail coat lined with titanium
• Overbearing bitch with no tail to credit
• Asserting positively
• Forcibly asserted mac I'd got was defective
• Opinionated scoundrel has mum twitching
• Giving opinions in arrogant know-all way
• Positively something for 10 across to lie on, I see
• Certainly that's the way to be bitchy with a twitch