Twitter don’t offer an “official” way to do this but there is a simple hack that you can use. First of all you need to create a normal tweet. This should have an image screen grab of your simpleERB booking widget. Then you want to add the url for the widget. You can find your widget URL here
Then add a call to action like “Make a reservation with us now!”. Then you want to pin the tweet. You do this by clicking on the arrow at the top right hand side of the tweet and selecting “Pin this tweet” from the drop down. We do it at the top of our @simpleERB page on Twitter
See a sample and image below for a pinned tweet;