It actually is if you look at the depth required for a successful nasal swab. It isnt just around the tip of your nose. They are up by your eyeballs deep with it. Here's a diagram of the nasal swab. It's several inches into nose. There are some that are only about 1-2 inches, but you adults are likely getting the 4 inch one. Anal swab is similar, but only the 1-2 inch penetrative. As far as medical procedure, its not even remotely painful or intrusive as say a prostate exam. Similar to rectal thermometers.