This DJ-EasyContact style (theme), let's you display the contact form in nice popup/lightbox window and the button to open it is visible in the bottom right corner.
If you want to check how it works, simply click the blue bubble and see what happens.
In the left column you can switch to different styles to see how they look like.
Below the menu with styles you'll find the different variation of the module with the same style applied.
If you want to try it download DJ-EasyContact free contact form module for Joomla.