The reclusive reality star made his app debut, under a rather rude handle, on Monday with a selfie video appearing to be in good spirits laughing and smiling.
Kardashian's girlfriend Blac Chyna took to her own account to encourage fans to follow his account, but had a a few choice words.
In a NSFW video posted the same evening, Tyga's former fiancée delivered a warning to female followers by saying, "Lemme tell you all something, don't be snapping my boo that p---y. I ain't f--king playin."
The model later took to Instagram to share a sexy new photo of her wearing a black fishnet dress – and not much else.
In the image, Blac Chyna crouched in front of a mirror, with her bare bum completely visible.
Source: Blac Chyna Instagram
"Eat your heart out," she wrote.
The new romance, which went public on Jan. 25, has caused tension between Kardashian, 28, and his sisters, specifically Kylie Jenner, who is currently dating Tyga.
Kardashian has been out of the spotlight for the past two years as he struggled with depression, 100 lb. weight gain and a health scare that saw him hospitalized and diagnosed with diabetes.
"Rob has been lonely for so long, so of course it's great for him to spend time with someone other than his sisters," a source told PEOPLE.
Kardashian's Snapchat account comes days after he reportedly drove to Texas to pick up Blac Chyna on Saturday, after she was arrested on Friday evening.
The mother of one was taken into custody on charges of public intoxication and possession of a ecstasy pills in Austin.