I choose to believe that they are literally watching the same dream.

Meanwhile, Piper is dreaming that "Oh, Guy-kun, it's not like I like you or anything, baka!"

Whuchu thinkin' about "Cool Guy"?

Are those tattoos? Cool.

Piper is smiling in her sleep. I can only assume she’s dreaming about setting stuff on fire.

Or more wholesomely, possibly dreaming about hanging out with Archie, doing something entirely not annoying.