Hi Flibbles_in_tha_h00d,
Thank you for reaching out to Microsoft Community.
In pairing the Surface Headphones with multiple devices:
While the Headphones is paired on your other device, please try to press and hold the power button of the headphones until you hear a notification that it is ready to pair.
For the Mac set up:
Please see this page for the steps to Set up Surface Headphones
You may check these other pages also for more information:
Fix problems with your Surface Headphones
Fix problems with setting up your Surface Headphones
If this answer your question, we highly encourage you to inform our Community by clicking on Yes or marking my post as an answer. This will help other members who may have the same issue as you. Otherwise, don't hesitate to update us so we can further assist you.
Kind Regards,
Marrion Y.