"Populate the Earth" joke

One day, God and Adam were walking in the Garden of Eden. God told Adam that it was time to populate the Earth.
"Adam, you can start by kissing Eve."
"Lord, what is a kiss?" asked Adam.
God explained, and then Adam took Eve behind the bush and kissed her.
A little while later, Adam returned with a big smile and said, "Lord! That was great! What's next?"
"Adam, I now want you to caress Eve."
"Lord, what is caress?" asked Adam.
God explained, then Adam took Eve behind the bush and caressed her.

A little while later, Adam returned with a big smile and said, "Lord that was even better than a kiss! What's next?"
"Here is what gets the deed done. I now want you to make love to Eve."
"Lord, what is make love?" asked Adam.
God explained, then Adam took Eve behind the bush.
A few seconds later, Adam returned and asked, "Lord, what is a headache?"