"Went down to 'sh!'" I originally learned as went down to "Hmm-hmm" -- ie a euphemistic noise, as 'sh' = 'hush' or 'hmm-hmm' for a supposed avoidance of pronouncing the actual word; from time when "Hell" was thought of [facetiously, I suspect] as a very naughty(!) swearword.

≈M≈