Pretty sure we are the only animals with pink rings around our mouth. It’s flipping weird.
It probably helps with verbal language understanding as humans often use mouth movements to interpret words (see McGurk effect). But I still think it’s weird.
Big pink rings.
Fun fact: when two people kiss, they create a long tube that starts and ends with an anus.
So you could also extend that tube woth a third person?
Ever performed a double butt kiss?
Plot for human centipede right here.