1. A phrased used to state that you have to poop.
2. To take a poop and to finish in the fashion of pinching your butt-hole together to pinch off the end of a hanging turd.
3. To end a poop early
1. Hey Bob! Wait for me on the first tee, I'm gonna go pinch a loaf.
2. Staring at the bread through the bakery window reminded Curtis that he still needed to pinch a loaf.