I can't see that video you posted right now, but I did Google Lyen Wong. She's a figure/fitness competitor, which means a few things.
1) When she's competing, she's got a ridiculously low body fat % Like, the kind of body fat percentage that can only be achieved by eating only boiled chicken breast and celery for 2 months and leads to you not getting a menstrual period.
2) She works out, a lot. And with heavy weights. Which is the only way to build that kind of definition (along with lowering your body fat percentage).
As for how to get an amazing butt, the man that knows it best is Brett Contreras, aka, The Glute Guy. (
http://bretcontreras.wordpress.com/)
Focusing on big, compound exercises (like squats, and various deadlifts) is key. As well as things like glute bridges. Also key? Using heavy weights and practicing progressive overloading (ie, constantly increasing the weight you're using).

We'll just not tell H about this little fact, m'kay?
