Physical placement isn't important. Psychologically, it's the same. What it means is that for the entire duration there is someone paying close attention to (and potentially judging) everything I do. No downtime, no zoning out, focus and performance for an extended period.

IM notification from an old teammate pops up complaining about my boss? Seen.

Switch to a window with my personal email and they can see that thing I just bought or that recruiter I've been talking to? Seen.

I type a stupid thing that will never work? In the 5-30 seconds before I realize it, seen.

It doesn't matter if I trust my pair. That's not how the brain works.

Well you won't have IM or email open while pairing :) you'll be focured on the conversation you're having with your pair. They're not watching you you're collaborating

As someone who pair programmed 8 hours a day for 10+ years, it’s important to note that there is an ebb and flow. Sometimes we were collaborating fully. Sometimes one of us got up to make coffee and looked at Instagram on their phone for 20 minutes while the other tried to get tests to pass. Then we reunited and caught each other up. It’s easy to dwell on the intense part of pairing, but it’s just as important to purposefully acknowledge your humanity and expect to take real actual breaks and go sit in a comfy chair and zone out for a short while or go to a doctor appointment or chat up another person at the water cooler for a bit.

8 hours a day pairing means that pairing is the default, but it’s not the only thing that ever happens.

also: 8 hours/day pairing meant 16 hours/day not working at all in my case. Really really really not working. Not checking Slack. Not trying out some crazy idea. Not working at all.