If you're using the Earn.com Gmail integration but want to manually choose which emails that are sent to you get bounced, you can switch off the "Bounce new senders" toggle on your Bounce Settings page.
How to disable automatic email bouncing
Easily toggle between automatic and manual bounces from your Bounce Settings page
How to manually bounce an incoming email
Once your account has enabled manual bouncing of emails, you can bounce emails in one click from Earn.com:
To bounce an email back to the original sender, press the “Accepted” button on Earn.com