There is an old question on Christianity.SE which I suggested that it should also be asked here - since we don't migrate OLD questions. In doing so, I noticed that the OP hasn't been really active and I suspect that it will never be asked here. With that said:
Genesis 24:2 NIV
One day Abraham said to his oldest servant, the man in charge of his household, “Take an oath by putting your hand under my thigh.
Genesis 47:29 NIV
As the time of his death drew near, Jacob called for his son Joseph and said to him, “Please do me this favor. Put your hand under my thigh and swear that you will treat me with unfailing love by honoring this last request: Do not bury me in Egypt.
Leviticus 7:33 NIV
The right thigh must always be given to the priest who offers the blood and the fat of the peace offering.
Is this a translation concern? What do they REALLY mean?