Sewing holes are pushed through the calf with a saddlers awl. 
 If I also make a hole in my finger, the blood remains
as a testament to my occasional flight of fancy.

Many leather workers succumb to puncture wounds every year

On the left, finished with saddle soap, dubbin, and a light coat of carnauba wax.  On the right, a bloody
(my saddlers awl is sharp) wallet ready to saddle-stitch.