Hi, I'm not sure what you mean by "stash on demand", but you can choose which of your open tabs to stash by Shift+Clicking or Ctrl+Clicking to select tabs in your Firefox tab bar (or Cmd+Click instead of Ctrl on the Mac), and then clicking the "Stash tabs" button in the toolbar. Or if you only want to stash the current tab, click the "Stash this tab" button in your address bar (instead of the toolbar).

Hope this answers your question, and if not, feel free to open an issue on GitHub: https://github.com/josh-berry/tab-stash/issues/new/choose . Thanks for your review!