Exactly on the same spot that Gaga has, I have a tat on my left arm of inner side.
As for Gaga's tat, it's written in German and it says (in English)
"In the deepest hour of the night, confess to yourself that you would die if you were forbidden to write. And look deep into your heart where it spreads its roots, the answer, and ask yourself, must I write?"
She's got an inspiration from a poet and a philosopher Rainer Maria Rilke.