"Shake It Off" indeed!

Three months after giving birth to twins Moroccan and Monroe, first-time mom Mariah Carey flaunted her shrinking post-baby body in a TwitPic posted Saturday.

Wearing a teal tracksuit, a low-cut V-neck and pink running shoes, the 41-year-old singer went "jogging puppy style" to shed the last few pregnancy pounds.

"My body went through so much," Carey said during a HSN appearance in July. "I was so uncomfortable."

"I'm kind of proud of myself. I really am -- sorry, pregnant with twins is different than anything! [People] were always saying to me, 'Oh, but it's all worth it!' Yeah, but it's easy to say when you're not the one whose feet are this big!" Carey, who wed Nick Cannon in 2008, added. "It turned into a really difficult time."