What makes it possible for some medication to be absorbed under the tongue?

Sublingual administration involves placing a drug under your tongue to dissolve and absorb into your blood through the tissue there. Buccal administration involves placing a drugbetween your gums and cheek, where it also dissolves and is absorbed into your blood.

Hiv can be transmitted through oral sex. you can get hiv through vaginal fluid and semen. if you have an open sore or cut in or near your mouth and an you get the semen or vaginal fluid of an infected person in those cuts or sores, you can get hiv

Sorry man that a really hard one you got there