What is another way to say back and forth?

Here are some alternatives to "back and forth," depending on the context:

For physical movement:

* To and fro

* Reciprocating

* Alternating

* Swinging

* Rocking

For conversation or debate:

* Exchanging views

* Trading arguments

* Debating

* Discussing

* Bargaining

For mental processes:

* Fluctuating

* Oscillating

* Shifting

* Alternating

For actions:

* Reciprocating

* Reversing

* Interchanging

* Alternating

More specific:

* Ping-ponging (for rapid exchanges)

* Yo-yoing (for repeated up and down movement)

* See-sawing (for alternating between two positions)

The best alternative will depend on the specific context of your sentence.