If you're unable to install OneNote on your work computer, there's a good chance you frequent OneNote online to get your collaborative brainstorming fix. The service has been in place for a while, giving OneNote users the option to work on their projects with nothing but a browser and some spare time.
The service has recently introduced the "draw" feature, letting people scribble on their online notes the same way that they scribble on their OneNote program. Whether you're an artist or just prefer to write out your notes rather than type them, this new feature is going to let you draw to your heart's content.
The feature is available on Edge, Internet Explorer, Firefox, Safari, and Chrome. It began rolling out at the beginning of the month, so it should be ready for you now.