It's hard for a lower back tattoo not to be sexy on a girl. Their placement makes it the perfect sexy tattoo.
If you're considering a back tattoo and don't want them to be too cutesy, there are designs out there for you that will really stand out when you want them to. Just be aware that these tattoos are visible whenever you bend over in most casual outfits so dress appropriately when you don't want to be the center of attention.