After performing this achievement, the action will need to be done 19 more times;
After learning how to properly execute a cinematic dodge from the tutorial you'll earn this achievement fairly early. Whenever you get close to a Taken you'll want to time your dodge just right, pressing the LB button away from your enemy to cue a Slow-motion dodge.
Note: This achievement is also known to be somewhat glitchy and may take several attempts before popping your 25G achievement!