I've seen this in videos and read about it in BDSM fiction but almost always involving a female sub. In reading about it's origins as a torture technique in the Spanish Inquisition or even during the US civil war (riding a rail) it seems it was often used on males.

Wondering if any subs here have experienced it or if any Dommes have used one on a sub? I'm a huge fan of predicament bondage and this seems like it could be particularly wicked. eek

One account of use on a male here....

https://www.getdare.com/bbs/archive/index.php/t-823.html