You don't hear it too often where I live because people don't often discuss retching, but it is a euphemism in my area of the USA too.
Even without the slang term,
Ralph sounds like an onomatopoeia for the act of vomitting.
Prior to getting on this website, I hand never heard that
Randy was a slang term for anything, but from what I've heard on here it is pretty common in Britain and parts of the US.