What's a little playful joking between sisters?
In the video, Kendall, 24, wears a powder pink wig while applying lip product that extends far beyond her natural lips onto her cheeks and chin.
Kylie, 22, is known for her plump lips and has previously revealed that lip liner was the secret.
"I love overlining my lips," Kendall said, imitating Kylie's voice. "This is how it all started."
"Literally, like, I just overlined my lips and everyone was wondering what I was using," continued Kendall, still lathering on the lip liner.
Next, Kendall started sloppily applying bright red lip gloss, laughing as she spoke.
"You can mix the shades," she explained. "I love mixing."
Kendall used Kylie's products -- from the beauty mogul's company, Kylie Cosmetics -- for the gag video, including a mirror with Kylie's branding on the back.
"Oh my God, it feels amazing on my skin," Kendall joked before wiping lip gloss across her front teeth. "It feels so f--king good."
Not only was Kendall laughing throughout the video, but crew members behind the camera could be heard laughing, as well.
The video concluded with Kendall -- having cleaned off her face but still wearing the wig -- calling Kylie over video chat to show off her new look.
"Oh my God," Kylie said upon seeing the pink hair. "You look good cute as Kylie. It looks amazing."