Tor is for anonymous browsing. The flash plug in is a third party plug in. This can compromise your anonymity. If you install third party plug in you may as well not use Tor.
If you want anonymity and the use of flash, I recommend using a livecd called TAILS (The Amnesic Incognito Live System). Everything to and from a computer that has booted into TAILS will be through the Tor network.
https://tails.boum.org/
Tor FAQ
I can't view videos on YouTube and other Flash-based sites. Why?
YouTube and similar sites require third party browser plugins such as Flash. Plugins operate independently from Firefox and can perform activity on your computer that ruins your anonymity. This includes but is not limited to: completely disregarding proxy settings, querying your local IP address, and storing their own cookies. It is possible to use a LiveCD solution such as or The Amnesic Incognito Live System that creates a secure, transparent proxy to protect you from proxy bypass, however issues with local IP address discovery and Flash cookies still remain.
If you are not concerned about being tracked by these sites (and sites that try to unmask you by pretending to be them), and are unconcerned about your local censors potentially noticing you visit them, you can enable plugins by going into the Torbutton Preferences->Security Settings->Dynamic Content tab and unchecking "Disable plugins during Tor usage" box. If you do this without The Amnesic Incognito Live System or appropriate firewall rules, we strongly suggest you at least use NoScript to block plugins. You do not need to use the NoScript per-domain permissions if you check the Apply these restrictions to trusted sites too option under the NoScript Plugins preference tab. In fact, with this setting you can even have NoScript allow Javascript globally, but still block all plugins until you click on their placeholders in a page. We also recommend Better Privacy in this case to help you clear your Flash cookies.
The Tor Browser Bundle does not work with Flash or other plugins by design. If you wish to run these plugins over Tor, you need to install Tor and configure your own instance of Firefox.
https://www.torproject.org/torbutton/torbutton-faq.html.en#noflash