How to prevent people hearing your computer sound when switching side


I usually connect to my customer directly with Team Viewer, we pay for a the licensing.

But sometimes I have to switch the control over to my side and since I am calling them with another app, they ALWAYS hear themselves and it's very annoying

Of course, I simply have to lower their volume on their side but it's still annoying to do.

How can I prevent Team Viewer sharing my sound (the customer hear themselves when they talk) when inverting the control to share my screen?