What is hidden in 3D image?

Last summer Ed met a woman while on vacation and fell head over heels in love with her. On the last night of his vacation, the two of them went to dinner and had a serious talk about how they would continue the relationship.
"It's only fair to warn you, I'm a total golf nut," Ed said to his lady friend. "I eat, sleep and breathe golf, so if that's a problem, you'd better say so now."
"Well, if we're being honest with each other, here goes," she replied. "I'm a hooker."
"I see," Ed replied, and was quiet for a moment. Then he added, "You know, it's probably because you're not keeping your wrists straight when you hit the ball."