The last verse of PERI-PERIWINKLE (or something very close to it) has already been posted as a separate song in the following threads:

Ach du lieber Augustin
Lyr Req: All the Little Angels
'Teasing' songs

However, I was surprised to see two versions of the pun, one using British pronunciation:

"are sent up" / "arse end up"

and one using American:

"ascend up" / "ass end up"

I would expect Australians to use the British pronunciation. I'm not sure about Canadians. What nationality is your informant? Can anyone explain two different accents in the same song?