Kourtney Kardashian Poses with Her Breast Pump In Las Vegas!

This video is unavailable because we were unable to load a message from our sponsors.

If you are using ad-blocking software, please disable it and reload the page.

This is how a mother of three celebrates her birthday in Las Vegas.

After her 36th birthday celebration in the City of Sin, Kourtney Kardashian shared an Instagram pic on Sunday of her sexily posed on a counter while wearing her breast pump. She captioned the pic with the classic tagline: "What happens in Vegas stays in Vegas."

PHOTOS: Star Shots! What's On Instagram?

This wasn't the only silly pic posted over the oldest Kardashian sister's birthday weekend. Her babies' daddy Scott Disick also shared an image of him and Kourtney holding cutouts of their own heads. "Goodnight Vegas," he wrote. 

VIDEO: Kourtney Kardashian Shares First Pic of Her Adorable Son Reign

The couple welcomed their third child, son Reign Aston Disick, in December 2014, and as was evident in one pool pic back at the Disick mansion on Sunday, Kourtney's bikini body is already on point!

NEWS: Kourtney Kardashian Is Back Down to 120 Pounds Just 3 Months After Giving Birth

One thing's for certain, this mom knows how to party!

Before she was posting breast pumping pics, Kourtney was posting the first photo of her baby boy. Check him out, below.