Different locations can mean different things to different people, but the butterfly's inherent triangular shape makes it well suited to accentuating certain areas of the female form. Remember, tattoos are like jewelry; they should be used to enhance the form, not hide it or sit out in the middle of nowhere. Stay away from single tattoos on broad, flat areas with little natural curvature (like the outer leg and thigh). Better locations to enhance the form are the small of the back, the back of the neck (just above the shoulder blades), and the inner wrist. If this is your first tattoo, stay away from areas directly covering bone (like the feet and shoulder blades). Such tattoos can be excruciatingly painful even for experienced customers.
While several small butterflies with spread wings will give the right impression, you can raise your bodywork to the status of true art by incorporating movement and flow. Instead of just repeating the same stenciled butterfly in several different positions, work with your tattoo artist to render several in various stages of motion, starting at one point and ending at another. You should aim to follow the body's natural lines (the line of the thigh to the lower back, or up the spine and across the shoulder blades), showing the same butterfly with evolving wing and body positions. The end result can be both dynamic and sensual, but easily concealed when need be.
In the modern context, tribal tattoos often represent a stylized vision of a certain mindset. The style can be quite powerful in its sublety; thick, blunt lines represent something akin to the yang (maleness, aggression and dominance), thinner and more flowing lines represent the yin (femininity and empathy). A tribal-style butterfly tattoo with thin and flowing lines (perhaps in the wing-tip area) juxtaposed with straighter and thicker lines (as in the wing veins) presents a pleasing tension of the yin/yang balance.
When you see a tattoo, bear in mind that you're not looking at ink on the skin; the ink is actually well below the surface. When the tattoo heals over, you're actually looking through the natural skin tone, which can be a problem for people of color. Colored tattoos tend to look very muted or discolored on darker-toned people, so stay away from white, orange, yellow, and green if your skin is too dark to support it. Red tends to get lost completely in anything but very fair skin. If you're dark-skinned, go for a black, purple or dark green design with solid lines and little shading.