Hello to all. I was hoping someone could answer a question about shiradi for me. Does anyone know how the mechanic for Otto's and Pin works to make it proc? Are there enhancments, or gear I could use to boost it to make it proc more often, and against higher level mobs?

I am currently running a level 25 first life pure human AA in FoTW. I want to twist Otto's and Pin. I've been using Otto's a lot but I've only been able to proc it once against a meaningful mob, (Hound optional in Servants of the overlord)

Any input would be appreaciated. Thank you