Less of a mixed idiom, and more of a funny mistake. Something that us British are always guilty of is self-deprecation. Self-defecation is another thing entirely.
Made up of
- Self-deprecating, and
- Defecation.
Source of this messed up phrase
A tip-off from @sayitwithsocial – social media consultant.
She pointed us to this brilliant twitter thread started by Joe Jeffries here:
My dad used to amuse himself in meetings by noting the mangled idioms of his management colleagues. Here’s some he found in his 1995 diary – verbatim and brilliant. #copywritersunite pic.twitter.com/NGhFmXxeYz— Joe Jeffries (@_joejeffries) January 12, 2018
Joe Jeffries