The problem with the buttocks and the breasts are that both of these areas are suspect to the additional laying down of adipose tissue (fat cells). Essentially, however, exercising these particular regions will generally firm and increase size of the muscles of these areas, especially if using the right exercising regime. You can tighten or tone your butt and your boobs. This is likely to improve their shape and appearance.
The muscles underneath your boobs are your pectorals and those shaping your butt are often called, "the gluteals".
Here are exercise suggestions from other contributors, they may or may not work:
Personally I have found that doing exercises such as push-ups and bench press builds muscle beneath the chest area allowing the breasts themselves to look firmer and larger.
Doing an exercise such as the squat or leg press enlarges and firms the gluteus maximus thereby leading to a great looking butt.
To make your butt bigger you should do leg presses, lunges, and single leg squats.
The butt is essentially so-shaped because of its muscle, unless you have a very great amount of fat - which will also contribute to a degree, but it will look sloppy. To build muscle in this area and at the back of the legs generally, great non-weight exercises include running up and down hills -especially sand dunes [better still], or climbing trees or running up and down stairs - especially 3 steps at a time.
Also, many here have mentioned lunges: they are certainly contributors; but a better exercise for the development of the gluteal muscles are jump squats. They are great for the gluteals and the legs generally, and for the lower back and stomach muscles, as well.
Lunges. Start with stationary lunges if you are a beginner and progress to walking and reverse lunges. Single-leg squats also seem to work. The biggest mistake is to use light weights, the heavier the weight, the bigger the muscle!
Do large amounts of sit-ups and twist sit-ups (sit up to the right and then sit up to the left).
You cannot make your boobs bigger, but you can RISE them by benchpressing, although too much of it or using too heavy of a weight could give you a manly looking chest (speaking in shape). Get a weight you're comfortable with and it should make your breasts rise some.
In addition to bench presses and twist sit-ups, push-ups will help your breasts.
From experience to help get that great "bubble butt" look is to do stairs! In cheerleading over the summer our coach made us run stadium stairs and I had noticed that my thighs were getting bigger and looking nice, and also my butt had been gettin bigger!
If you want a bigger butt you have to do a whole lot of lower body exercises such as lunges, squating (with heavy weights), walking and stairs. The butt is nothing more than a muscle, to make it grow you also have to put more food into your body, but mainly foods with a lot of high amounts of protein, plus you have to gradually increase the amount of calories you are eating (usually they suggest starting with 500 more calories than normal per day). The only way you won't see results you want exercising is if you aren't also implementing the suggested diet.