What are very good exercise to tone your butt?

I was wondering how to get a good looking @ss , my girlfriend likes themy butt but I think I'm losing it, I want to get a hood one but I don't want to lose it.
Like what excersise will make my butt looking good? Or how can u? Like a butt that a...

girl would love to have it on her boyfriend body, and squeeze

Squats and lunges, 3 x a week, 4 sets each time, 25 reps each set

There are plenty of exercises that work out the glutes...but the key to gaining muscle on the glutes is to concentrate on flexing them while doing the exercises otherwise you will be using your legs a whole lot more while only using your glutes as a secondary muscle...

Try wide legged squats with your toes pointed outward and flexing your glutes. Pelvic thrusts work as well. An olyptical machine, stairmaster or running at a incline will also build your glutes.