Kylie Jenner Sucks Kendall's Tongue Because Sisterhood Is a Deeply Personal Experience

They may fight sometimes, but Kylie and Kendall Jenner always have each other's backs -- and sometimes even each other's tongues.

Kendall Snapchatted herself sticking out her tongue at her younger sister on Monday, who decided to slurp it right the hell up.

Right. The hell. Up.

"She sucked my tongue... I'm dead," Kendall captioned the snap.

Meanwhile, the reality star siblings are having an eventful trip down under in Australia, where they appeared at a Sydney mall to this kind of fandom:

"I love you sweet Sydney. So much love in the air today," captioned the deafening video.

The trip did have its hiccup , their meet and greet was delayed 45 minutes when one woman allegedly threw eggs and tomatoes, a source tells ET. However, Kylie tweeted she knows nothing about any egg throwing.