[Stevenator.]

I believe that under the tongue is considered “sublingual”, and it’s not the same thing as oral, which does go to the stomach, and then a so-called first pass through the liver. I was always under the impression that sublingual transmission was due to the blood vessels under the tongue, but according to this Wikipedia entry, that’s only partly correct. (Apparently the absorption is through a mucus membrane, then it’s transmitted to blood vessels). 

Fwiw, I take Estrofem E2 tablets sublingual under the tongue, and Micronized Progesterone Suppositories rectally. I tried a broken capsule sublingually once, and it tasted like body lotion. 100% Yuck. 

https://en.m.wikipedia.org/wiki/Sublingual_administration