Using the pipe on a steel crank, you'd do it at 12 o'clock, and holding the bike as a fulcrum works fine.

I reiterate my warning about not doing it with an alloy crank. If you check my posts, you'll see that I'm not one that offers warnings casually. I'm usually then guy saying it's OK to ride.

But straightened aluminum cranks pose a serious risk of breakage, and the outcomes can be far worse than a cut on the ankle. The crank lets go when you have full weight on the pedal, and it's like when Lucy swipes the football away. Your foot will slam into the ground with enough force to damage foot and ankle bones or knee ligaments. Unless you're an experienced rider you'll lose control of the bike, possibly swerving into traffic, or simply dumping the bike.

Do my "Don't do it" isn't typical CYA boilerplate. It's a serious warning, that you'd be wise to heed. see a local dealer or bike co-op for a cheap crank.