My guess is that OP did indeed mean "knocking boots" as a reference to Operation Paperclip, where the US government granted amnesty to a bunch of Nazi scientists in return for pivoting their research to US national security purposes.

edit: source https://en.wikipedia.org/wiki/Operation_Paperclip

when I was growing up "knocking boots" meant have sex? (there was a whole rap song with that title). Which is what I assumed "squamming loins" was some british english version of.

It’s a metaphor in the same sense as “strange bedfellows.”

Whoops. I had thought it to be merely some unfortunate onomatopoeia. It's awesome that the word has so many actual meanings, if informal ones. But yes, "a thing involving 'mutual loins' that sounds like 'squam'"