As suggested by Aeribian here is something for the RP'ers
It is now possible to link multiple accounts and quick switch between them. In order to link accounts go to the
User CP and you will see Link to Another Account. Enter username and Password of the account you wish to link to and click on the Link Account Button. You can also see a list of all accounts you are linked to here and unlink.
In order to quick switch between the two, at the top of the page you will see something like this
If you click on the little arrow next to your username you will see a list of accounts that you are linked to like so
Click on the username you want to change to and you will be logged in as that account. In order to do this the page will refresh so try to remember to do it before you write that massive post and not before you hit submit