If a senator can't make it to the chamber, they often agree to "pair" him with a senator of the opposite party for votes. I don't think it's obligatory. It has to be agreed, for mutual convenience.
Pairing is done when two Senators intend to vote the opposite way on an issue and both will be away. It has nothing to do, and never has, with what you suggest.
I still don't know what you mean.
Does the GOP now have to have one semator sit out whatever Johnson misses?
Why?
sounds crazy