Once upon a time in China, lived two Chinamen.

One named "I Cum" and one named "No Cum".

"No Cum" marry pretty Chinese girl named "No Cum Tu".

For very obvious reason "No Cum" and "No Cum Tu" not have any children.

One day, "No Cum" went out of town on business and "I Cum" came over and
spent the night with "No Cum Tu".

That night "I Cum" came and "No Cum Tu" came too.

This make both very happy.

About 7 or 8 months later, "No Cum" see he about to become father but he not
know how come, so when baby come, he named it, "How Cum U Cum".

Of course, "I Cum" and "No Cum Tu" know "How Cum U Cum" came but to this day
"No Cum" not know how come "How Cum U Cum" came!

H/T: Bob