Stand near the wall and scrape up ice with your stopping edge, back and forth, back and forth. That way, you can dull it down enough to stop when it really counts.
I learned my lesson about letting the blades get too dull before sharpening a few years ago. They were new blades, so the rocker was different, and the blades were literally razor-sharp. I skated forwards, did a t-stop, no problem. Skated forwards, turned backwards and could not step forward or stop; had to let the momentum run out and use the toepicks. No more of that.