In a Sunday video on Instagram, Chmerkovskiy revealed the Lamaze experience was exhausting and overwhelming -- not to mention that Murgatroyd fooled around too much.
"Lamaz class went......interesting. @petamurgatroyd was the worst student in class, but I don't blame her cause it was a million hours long and we've been shown waaaaaaaay too much stuff! My hair is indicative of the 'stuff' we've witnessed. #traumatized #NothingToHashtag," Chmerkovskiy captioned the video.
In the video clip, Chmerkovskiy is talking to the camera as he walks out from a building and through a parking lot to his vehicle. The Dancing with the Stars pro's hair is all disheveled and he appears completely frazzled.
"Baby, what just happened? What did we do?" Chmerkovskiy asks Murgatroyd in the video.
"It was our first Lamaz class," Murgatroyd gently notes with a big smile on her face.
After Chmerkovskiy shakes his head side to side, he admits, "We got kicked out because Peta was misbehaving."
Murgatroyd let out a big laugh and then the bad boy of the ballroom continued, "And not listening to anything. That's what happened. This baby is going to be a disaster."
Murgatroyd is currently about 36 weeks pregnant and the baby, as Chmerkovskiy previously revealed, is due on January 2, 2017.
The parents-to-be got engaged in December 2015, confirmed they're expecting their first child together in June, and have been snapping adorable photos left and right of each other ever since.
Murgatroyd did not compete on the latest season ofDancing with the Stars since she's pregnant, but Chmerkovskiy finished Season 23 in ninth place with his celebrity partner Amber Rose.