The chorus I remember is:

"Marnie, Marnie, Please come home with me.
Now father's resting in his cups and mother's drinking tea.
Won't you come a-bundling, a-bundling with me."

Bundling was described to me as: before a couple was married, the woman would lie beneath the sheets and the man on top of them.

I suspect it had different meanings in different societies, but always it was a way to keep a couple separated while still maintaining the idea of intimacy.