I fed my feed back to my friend feed account. Each post showed up twice but that was it. No infinite loop, no endless recursion.
To speed the process, go to your page (i.e. friendfeed.com/yourusername), click Add/edit services, click the self-referential feed in the My Services list, then click Refresh Blog.
BTW I'm not encouraging anyone to actually do this. It was fun just to try out.