Kylie Jenner
Kylie Jenner (pictured) knows just what to do to get back at Blac Chyna, Tyga's ex, a source said. Getty

There’s not much love lost between “Keeping Up With the Karadshians” star Kylie Jenner and Blac Chyna, her boyfriend’s ex. The two have been regularly exchanging passive-aggressive social media disses, but the reality star has reportedly come up with a new way to rile Chyna.

The best way for Jenner, 17, to get back at Chyna, 27, is to show how “happy” she is with Tyga, 25. “Right now, the only way she can really get back at Blac Chyna is to show her how happy she is with Tyga. It frustrates her, but at the same time she knows being happy and positive is the best revenge,” a source told Hollywood Life in an exclusive report Friday.

But it doesn’t mean Chyna can’t get her digs in. When the “Kylie Jenner Challenge” went viral Chyna also chimed in. Except, she used giant wax lips and posted the photo to Instagram. Other teenage girls had sucked on items -- like shot glasses-- to give their lips a pout comparable to Jenner's, but Chyna was obviously making fun of Jenner.

“Kylie’s trying hard to stay strong and not let it upset her, but it’s tough,” the insider said. “She’s way more sensitive than she likes to admit. The things Blac and her friends say to her are very hurtful. They make her cry! But she’d never want Blac to know that.”

Aside from showing that she’s happy with Tyga, Jenner also posted a bathroom selfie to Snapchat wearing her boyfriend’s underwear from his Crisp Collection. “Not doing s---” she captioned one of the photos. She also made sure to hold up her shirt to show off her taut tummy, which is either a display of millennial-style narcissism or an attempt to dispel pregnancy rumors.

Follow me on Twitter @mariamzzarella