There is a 'Post Reply' button at the top of each thread (just before the first post) and another at the bottom of each thread's page (after the last post). Right next to the bottom 'Post Reply' button you'll now see a 'Quick Reply' button (if you're logged in). If you have javascript enabled on your computer, you can click this button to show the open the hidden dialogue box immediately below the button. Just type your message and hit either the Send or Preview button.
now my lazyness can increase