I've been on Opana 2 yrs now. Your tolerance builds fast from snorting. That's why I take a methadone/detox break every 3 months to get my tolerance down and get back to where Opana actually helps with my pain.
Anal use of Opana is probably a waste, as it is somewhat similar to oral use.
Have you tried switching brands? I normally get the white 10's, as they last a lot longer than the pinks/peaches.