A girl was extremely beautiful and shapely. So much, in fact, that her boyfriend liked calling her "BB" -- for "beautiful butt". She knew that not only did he like her, like her for her hiney, and like her because she was THE one for him -- that she decided to get a tattoo just for him.
She went to the tattoo parlor and had the artist put a large "B" on each butt cheek. Since boyfriend was out of time on business the tattoo had enough time to heal, and when he got back home she decided to present him with the visual gift.
She waited 'til he had settled in after work and then walked into the living room (where he sat) and said "Honey, I want to show you something that I did while you were gone" and promptly dropped her trousers and undies - and bent over so he could see her rear end. He looked for a full minute or two and finally said:
"Bob! Who the heck is Bob?"