Future Generations or the Next Butt

S had a social studies assignment to rewrite the preamble to the constitution in his own words.
It was a long and arduous process, for both of us.
But, he slogged on until this part.
"Mom, this says 'for ourselves and our posterity."
"Yes, what do you think that might mean?" I asked.
"Well, I'm not exactly sure. I know posterity means 'butt' and I just can't figure out why they're talking about butts in the Constitution. Does it have something to do with the freedom to pass gas?"
"No, dear, the founding fathers were not concerned with gaseous eruptions. The word you're thinking of is posterior not posterity."

We are going out to get a dictionary this weekend.