What is That?

A priest and a nun were traveling through a desert on a camel. After hours of traveling the camel dies. The priest and the nun make camp, and after days they realize that they are going to die. So the priest tells the nun, “Sister I have never seen a woman naked and I was wondering if I could see you naked." 

The nun says yes and takes off her clothes. Then the nun tells the priest, “Father I have never seen a man naked and I was wondering if I could see you naked." 

The priest says yes and takes off his clothes. Then the nun sees the priest's penis and says, “what is that?” and the priest says, “It’s my holy spirit, if I stick it in you it gives life” and the nun says, “Don’t stick it in me, stick it in the camel".