Lumber sitting

How does one put 16' boards in a car that only has 14' of interior space?

One quick stop at the local lumberyard for some needed wood and suddenly I'm recruited by Pete to keep the 2x4x16's from falling out on the way home. All three minutes home I'm sitting on the lumber while leaning over keeping the trunk door closed as much as possible. It was surprisingly hard and back/hand crampy to do.

* note, I'm pretty sure my method of lumber sitting/ leaning to hold a door closed is illegal and therefor you should not try it at home.