If you want to turn people on to folk give it some sex!

Depends on your own interpretation of (musical) sex I suppose. Personally, I find far more energy in say the Clancey stuff I heard as a kid than say KR songs I've heard.

and cut-glass enunciation.

I don't remember thinking about that as a kid. I just liked singing. Didn't care whether it was Welsh songs (I'm English but had my primary school years from 7 on in N Wales) or English ones.

I'd have thought there where some were Welsh first language, there would have been even more grounds for objection to cut glass English accents but I've no memory of any such thing.