Searching by a shard of synopsis - hint: bean bag chair

I'm looking for a story involving what I think were two parents spanking two girls (I don't know if they were sisters). Near the end, the mother demands the father spank the both of them in the girls room, but, in a sweet moment of mercy, the father decides not to, and chooses to slap a bean bag chair, while the girls pretend to cry.

Many thanks, if you can help me find the name!