According to Karl Rove's Twitter, you can send farewell messages to the outgoing president at gwbfarewell@gmail.com.
Since those messages will be vetted, if only so they can get the sheer number down to a manageable size, I've decided not to email my message, but instead to put it online, available to all, and likely to be archived. A permanent tribute among millions of permanent tributes.
Dear Mr. President,
Thanks to the efforts of your administration and its supporters to impose neo-conservative ideas of sexual morality on society, I have felt an increasing desire to stick Little Bluey in practically anything that wiggles.
I am typing this with my cock,
Bluey