They're both legal adults and "high school graduates" now, but when it comes to boundaries, the Jenner girls have a lot to learn.
We looked on in confusion as Kylie put her hand down Kendall's pants.
We watched in horror as Kylie sucked on Kendall's tongue.
We prayed it would all end when the girls closed out 2015 by with a photo of Kylie grabbing Kendall's butt.
But just when you thought it was safe to go back on social media without some incestuous weirdness being passed off as shock-comedy, KJ and KJ are back with with the most inappropriate twerking since Miley rubbed her stuff on Robin Thicke.
We're not sure why Kendall and Kylie persist in getting all handsy and...whatever this is with each other. (Buttsy?)
It's nice that they're so close and all, but have they learned nothing from their older sisters?
Public acts of sexuality are meant to be reserved for rappers, athletes and other people outside of your family who might be able to help your career.
Hopefully 2016 will find Kylie keeping her hands off both Kendall and Tyga and putting them on...hell, pretty much anyone who's around her age and not related to her.
We're really not picky at this point.