'Teen Mom' alum Kailyn Lowry, 30, says she 'loved every minute' of her mommy makeover after 2nd son was born

Kailyn Lowry is defining sexy for herself.

The Teen Mom star, 30, says that her "definition of sexy has definitely changed" over the years.

"Now it's more about being confident and feeling good in your own skin," she explains. "When I was younger, it was more about how I looked and what other people said about me or felt about me. But now I feel sexy on my own. I don't have to rely on someone else's opinion to make me feel good."

Lowry admits that it's not always easy feeling sexy as a mom to four kids between the ages of two and 12.

"Feeling sexy every day is definitely a challenge for me in motherhood," she notes. "I always have 'mommy' things to do, so by the time I have alone time, I don't feel sexy. It's really hard. But I did a boudoir shoot last year and it was one of the most empowering shoots I had ever done. The photographer was phenomenal...It was really awesome. It was the most empowering and sexy I had felt probably since becoming a mom."