Blac Chyna's romance with Rob Kardashian certainly isn't cooling down.

On Wednesday, the 27-year-old model posted a steamy pic of her getting intimate in bed with her beau.

WATCH: Rob Kardashian Flirts With Blac Chyna in New Snapchats

In the photo, which was taken using a selfie stick, Rob, 28, nuzzles into her chest and tightly grabs onto her booty.

While it's hard not to focus on the image itself, many fans couldn't help but comment on the caption. "Missing Bae," it read, accompanied with a diamond ring emoji.

Within minutes, her post fueled rumors that the two might be engaged, with users commenting things like, "Bae??? Ring???" "What's the engagement ring for though?" and "Guess she made it official!"

WATCH: EXCLUSIVE: Rob Kardashian Is 'Madly in Love' With Blac Chyna

Chyna first sparked engagement rumors on Monday, when she was spotted wearing a massive sparkler on her left ring finger -- which you can slightly make out in a few photos posted to her Instagram -- at the Trinidad Carnival in Spain.

While Chyna and Rob have not yet commented on the rumor, it's clear that these two have fallen for each other fast. Just last week, the lovebirds -- who got together last month -- appeared as happy as ever in Los Angeles, smiling and laughing during Chyna's risqué bikini-clad photo shoot for 138 Water by DRE.

"The two definitely have a connection," a source told ET, adding that Rob was "sweet and humble" while supporting Chyna at her gig.

WATCH: Rob Kardashian Supports Blac Chyna During Beach Photo Shoot