Is there seriously a machine called "The Butt Blaster"? Yes. Yes, there is. And sadly enough, it's a favorite machine of the women in the gym because they are working towards a shapely rear. This is just like all of the other time wasting machines, with the major exception that it does not have it's place in rehabilitation. This truly is the biggest time wasting machine in the gym. Period.
So what's so wrong with the Butt Blaster? First and foremost, your genetics determine the shape of your derriere. No matter how many squats, lunges or reps on the Butt Blaster you do; your DNA is the determining factor of the curve (or lack thereof). Second, like the other time wasting machines, you can achieve dramatically different results with balance and stabilization exercises.
The primary goal of most women is to decrease the size and "tone" the shape of the rear-end. By incorporating stabilization training, an individual will burn more calories, while utilizing multiple muscle groups simultaneously. In essence, you get more bang for your buck. Simple reps on the Butt Blaster isolate the glutes and hamstrings, burning far fewer calories. If your goal is size and strength, this might be a machine to consider. But, only if the smith machine is being hogged. And even then, you would be better off doing something else.
Other aspects of the machine are of course, the biomechanics. Much like the prone hamstring curl, it is difficult for the majority of gym goers to isolate their core, protecting their spine during this exercise. You'll notice a lack of core strength when an individual kicks back and the low back dips or sways. Oddly, the machine actually fits a small percentage of exercise enthusiasts appropriately, causing an exaggerated dip. This dip can be very dangerous because not only is the body moving ineffectively, but the L5/S1 disc is being compromised. This ultimately results in the development of a disc injury (bulging disc) and subsequent back pain.
If you really want to kick your butt (seriously) the exercise that will always do it is the Alternating Forward/Reverse Lunge. This keeps your Target Heart Rate up higher, thus burning more calories and decreasing your body fat. It's an intense exercise that incorporates all aspects of fitness: strength, power, stability and balance.
So really, stay far away from anything that claims to "blast your butt".