Hello Erdal,
The player that you see on our website is the default player in your browser. We basically just say "show video here" and then your computer/browser translates that into the player you see without any input from us. Therefore, as soon as your browser manufacturer adds this feature, then you will see such a button.
My recommendation, however, would be to download The PM PrepCast to your phone/tablet using a podcast app. Look in "Module 00.1: Important Documents, FAQ and Tutorials" where we have instructions on how to download and access the PrepCast on your phone. Most podcast apps that I have seen already offer a forward/backward feature. Additionally, you now have all the videos on your phone/tablet and can watch them even if you are offline.