Level Up (A5E) Back to back, do only you benefit? Or your ally too?

[Valrei]

So I ran into the problem that the English language does not have a plural for "you", the text on Back-to-back (page 441) reads
"While back-to-back
with an ally it is harder to be caught off guard,
and you cannot be flanked. As long as neither you nor
your ally move, your passive Perception is increased
by 2 until either the start of your next turn or when
one of you moves."

In my logic it seems logical that if you are standing with your back to their back, they are also standing with their back to your back, right?
So I read this as "you" plural, as in "both of you", but it doesn't state that. Does it mean only the player taking this action cannot be flanked and has more passive perception? Or does it count for both players?

 

[W'rkncacnter]

it looks like it doesn't matter, since if you're back-to-back with an ally then they must, necessarily (both in terms of the action and in a realistic sense), also be back-to-back with you, meaning the passage applies individually to the both of you regardless.

 

[Morrus]

Yes, you can't be back to back with somebody and them not be back to back with you.