Not a colloquialism this one,however a true, and witty classic from my Mother in Law.
She had one of Gino Di Campo's pasta based cookery books bought for her at Xmas
She refers to him as " that Dino Di Cappucino"

Colloquialisms aside, that's really funny about your mum in law's new name for Gino de Campo.
I have many a tale of names my mum in law used to change. These were affectionately know in the family as 'Doris-isms'.
For example.....
After having her hair shampooed and set she'd say she'd been 'conifered' . I'm sure she meant coiffured but her version was better!
If she had a headache, she'd take two parasols. Imagine trying to swallow those!
And I read a really funny one recently in Readers Digest where a woman was trying to find a hat for a wedding. She wasn't successful in finding one to suit her so she told her daughter she'd just wear a fornicator instead. Oooh get her!