Unless you are using doing very light workouts, e.g. bodyweight, you should rest longer than 48 hours.

If you are lifting weights and regularly increasing the weight used, as you should do for continued improvement; then only work your legs twice a week.

To increase the focus on your rear:

. Squat: stick your butt out when desending into a squat, as if you were reaching back to sit on a chair.

. Lunges: Step back like this

I also recommend doing an exercise like back extensions. It works your leg biceps, rear, and the important low back muscles.

If you don’t workout at a gym, you can do back extensions on a table, with a blanket as a cushion and with a partner holding your legs.

Toning muscles – Exercising will firm-up muscles, but if you are overweight, remember exercise does not spot reduce. Fat reduction through a healthy diet is your biggest tool in looking better.