also can you explain me the routine?

first you cold read their body language, just look for signs of mirroring (when they are in rapport they will both do something similar)

when you see it, just say, wow you guys are alot alike, you guys act just like best friends

when they ask what you're talking about, or show interest in what you said just keep at it

no seriously, you guys act just like best friends, infact let me do the best friends test on you

then if they are down, you just say, let me ask you both a serious question... do you girls use the same shampoo? if they look at each other before answering, you just say, see! you passed!, you guys looked at each other before giving your answer, it's a sign you are best friends

if they don't look at each other before answering, just tell them they failed, and tease them about not being the best of friends