I've never really pair programmed - I've worked on joint projects, of course, but collaboration occurs over discord/github. I'm intrigued - what does this actually consist of? Does one person write one function and another write the next while you chat about what needs to be done?
We tend to work on one 'thing' at a time. Sometimes that means we're both/all on the same few lines of code writing a new function - at which point one person is usually doing all or nearly all the typing. If you then need to go define a constant somewhere else in the code or something the other person does that so you don't have to pause. Other times one thing involves code in various places because you're doing something like changing what arguments a function takes, or fixing compiler warnings, and we do spread out and handle instances of the thing we're fixing as we come across them.
Lines of code per second it's closer to one person than the 2 or 3 people involved, but the quality of those lines definitely improves a bit as people spot each-others mistakes/less than optimal choices. (Edit: But I'd emphasize we're doing this for fun, not to maximize productivity)