A naive young girl goes into the doctor's office. She says, "Doc, I'm
   getting married and
   I'm a little inexperienced, so I'd like to ask you a few questions."
   He says, "All right."
   She says, "All right...what is that thing that hangs between my
   fiancé's legs?" The doctor
   says, "That's the penis. The male organ, the penis." She says, "Okay.
   And what is that
   big red knob at the end?" The doctor says, "That's the glans. The head
   of the penis, the
   glans." She says, "Okay. And what are those two round things, about
   twelve inches
   behind the head?" The doctor says, "Well, lady, I don't know about
   your fiancé, but on
   me, they're the cheeks of my ass."