Two very useful expressions for (often useless and unproductive) reciprocal actions are:
1) to and fro
2) back and forth
Make sure, however, not to mix and match them!
NOT: “They threw insults back and fro.”
But: “They threw insults back and forth.”
With “to and fro” spelling is tricky when it switches word classes. If you want to use it as a noun or verb, look it up in the Oxford English Dictionary to make sure you’re sticking the hyphens and -s endings in the right places.
Example: the to-and-fro of the haggling process
Jason Blake and Monika Kavalir
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