In this video guide I will show you how to hit 30 enemies in the groin during tactical time dilation. To use TTD you hit the RB button to start the slow motion. Next
hover over an enemy to see the "weaken" effect pop up. Some creatures have these as well, but humans it's much easier on. Once you shoot them you will know you got it by their reaction. They will bend over in pain and stagger a bit.
There are some perks that will make the TTD duration longer and regenerate faster. So keep an eye out for those to make it easier. Also some companions have some similar skills, Parvati in particular has one.
A very important note when going for certain achievements in this game. This achievement might not count if you try it on the same exact enemy. I know for certain killing the same one for weapon achievements will not count. So keep this in mind.