Trash Talker Achievement
Taunted 50 gang members
To taunt a gang member, walk up to them and set your reticule on them. Then, hit to perform a taunt. You will know you've done it correctly when your gang notoriety goes up slightly and they attack you.
The easiest way to get this is to taunt your own gang members. If you equip your pistols so your crosshair shows, look at a gang member. You'll notice that a green X appears. Taunt him until it turns into a red crosshair. From then on out, every taunt counts towards your achievement. The fastest way to do it is to taunt, move your joystick slightly during the taunt to stop the motion, taunt again, move your stick slightly again, and so on. This takes about 3 minutes for the achievement.
You do not need to taunt 50 different people, just perform 50 taunts. You can check your progress by going to the Pause Menu and selecting 'Info' > 'Diversions' > 'Stunts' > 'Combat Tricks' > click 'Taunting'.
-Thanks to APerfektFIaw