JOEL - All you can tell them is that what they said was incorrect, because you have personally witnessed the ceremony, and then leave it at that. It would be hard to satisfy most people's curiosity about everything that happens in the temple without desecrating the sacredness of the temple ordinances. If they really are your friend they will accept this. If they insist on knowing more then tell them they will have to talk to the missionaries, join the church, and wait a year or so to find out for themselves, the same as every other convert must do.
There is a pamphlet put out by the church called "The Purpose of the Temple" that you could give them to learn more about it. You can find it at the following web site: http://www.geocities.com/Athens/Acropolis/1890/The_Purpose_of_the_Temple.htm
Also see the talk by Boyd K. Packer, “The Holy Temple,” Ensign, Feb. 1995, 32.