What is hidden in 3D image?

Two couples were playing cards. Jeff accidentally dropped some cards on the floor. When he bent down under the table to pick them up, he noticed that Dave's wife, Sandy, was not wearing any underwear! Shocked by this, Jeff hit his head on the table and emerged red-faced. Later when Jeff went to the kitchen to get some refreshments Sandy followed him and asked, "Did you see anything under the table that you liked?"

Jeff admitted, "Well, yes I did."

She said "you can have it, but it will cost you $100."

After a minute or two, Jeff indicates that he is interested. She tells him that since Dave works Friday afternoons and Jeff doesn't, that Jeff should come to their house around 2:00 PM on Friday. Friday came and Jeff went to her house at 2:00 PM. After paying her the $100, they went to the bedroom, had sex for a few hours and then Jeff left. Dave came home about 6:00 PM and asked his wife, "Did Jeff come by this afternoon?"

Totally shocked, Sandy replied, "Yes, he did stop by for a few minutes."

Next Dave asked, "Did Jeff give you $100?"

Sandy thought, 'Oh hell, he knows!' Reluctantly she said, "Yes, he did give me $100."

"Good," Dave says.

"Jeff came by the office this morning and borrowed the $100 from me and said that he'd stop by our house on his way home and pay me back. It's so good to have a friend you can trust."