In the video, shared to Kylie's TikTok account Thursday, Kylie is opening birthday gifts when Kim interrupts her sister to ask if she can take a shot. To the partygoers' surprise and applause, Kylie agrees, and later in the video, to the screams of "Happy Birthday," Kim can be seen lifting her shot to cheers her sister's big day.
It wasn't long after taking a sip, however, that the 41-year-old SKIMS founder spits out the shot, as her shock quickly turns to laughter over what's just occurred. Kim struggles to gain composure, coughing and hanging on to the table in front of her to steady herself after the strong shot.
Elsewhere in the video, Kylie, Kim, their mom Kris Jenner, Kylie's daughter, Stormi, and Kim's daughter, Chicago, and friends LaLa Anthony, Stassie Karanikolaou and more, are seen partying the night away on a yacht Kylie rented out for the occasion. Before taking a shot with Kim, Kylie took a shot with LaLa and other party guests, who joked that they were taking 25 shots for Kylie's 25th birthday.
Kylie's birthday party came after a slew of tributes were sent her way in her honor. From Kris, to Kendall, Travis Scott and more, the whole Kar-Jenner circle of family and friends celebrated Kylie.
As for Kim, she shared more shots of the two partying it up -- with shots in hand -- on what looked like a recent trip.
"Happy Birthday party gal (in LaLa’s voice this whole trip lol)," Kim wrote. "Every year you amaze me at how wise, protective of your loved ones and just how generous your heart is. You are so special and one of one. You have so much love and happiness in your love that I pray for this forever."
A source told ET over the weekend that the pair split after the "spark" between them had "faded."
"They had tons of chemistry, and still do, but she kind of wants to be single and date. Kim still adores Pete and will always be friends with him. She still thinks he's the nicest and sweetest guy in the world and there's no drama or anything weird between them now."
The source said that Kardashian felt like Davidson was "the extreme opposite" of her ex, Kanye "Ye" West, therefore the relationship was "good for her."
"She initially thought it would be a fun fling, but then it got more serious when they were spending so much time together," the source added. "Kim wasn't feeling like she was willing to settle down with him just yet."