talk out (the side of) one’s neck
v. phr.— «It’s obvious you haven’t seen X and are talking out the side of your neck, to boot.» —“Re: spike lee & boston celtics” by Robin L. Gibson Usenet: rec.arts.movie Nov. 20, 1992. (source: Double-Tongued Dictionary)
Further reading
What if, instead of being an inanimate object, a dictionary were alive? That’s the idea behind a lavishly illustrated new children’s book called The Dictionary Story (Bookshop|Amazon) by Oliver Jeffers and Sam Winston. This is part of a...
Cat hair may be something you brush off, but cat hair is also a slang term that means “money.” In the same way, cat beer isn’t alcoholic — some people use cat beer as a joking term for “milk.” And imagine walking on a...