Your Webmaster's Merry Introduction to Sounds

Greasing up the sphincter with some generic brand K-Y* is the first step. Here the technician is applying K-Y to his gloved finger. He'd never slip a dry or an ungloved finger into the rectum. (The angle of the photograph makes it look otherwise.)

Back side insertion is done first so that we can get that shit out of the way for safety's sake.

* We use one time packets of  sterile lubricating jelly for safety and convenience.