Put your ssn, the form # and the year it's for on the memo line and on the back.
you're not allowed to write on the back of checks except in the endorsement line.
And you're not endorsing.
Skip the paper check and do it online directly:
https://www.payconnexion.com/pconWeb/public/session/authentication_input.action;jsessionid=46E0A03DDA9D38E97CC6053468046D9D.tomcat_00081119_8120