An incredibly stupid phrase meaning 'brainstorm' which no-one uses and very few people have even heard of.
The word 'brainstorm' was not banned from UK schools you idiots. It was deemed offensive to epileptics by ONE local council who opted not to use it in their public discourse in favour of the term 'thought shower'. This was ridiculed by everyone everywhere, including epileptics, for being so stupid that even the Flat Earth Society and the Super Sweet 16 fanclub pointed and laughed.
The phrase, while rarely used, is still highly reactive to the point where it reduces the IQ of both speaker and listener whenever used.
Politician: We'll be having a thought shower tomorrow.
Normal person: Damn, I think I just got dumber.