To gain this achievement you must use one of the 12 special characters, after unlocking all of them. The special characters are the 'soapbox' minor characters found within and around Los Santos and are unlocked by speaking to them. Here I will list each characters location.
(The following information is from gta.wiki.com
https://gta.fandom.com/wiki/Soapboxers#Known_Soapboxers....29)
You may also refer to this video, all credit goes to 'GTA Series Videos'
Andy Moon- He appears in Vespucci along Magellan Avenue, near the Nut Buster restaurant and just south of the Beach Combover Barber shop, although he may appear in other places.
Baygor - He can be found on Portola Drive in Rockford Hills, near the Vangelico Jewelry Store, sharing information about Epsilon with passers-by.
Bill Binder - He can be found outside of Willie's on Procopio Dr in Paleto Bay
Clinton - Clinton is found on the corner of Marina Drive and Armadillo Avenue
Graham/Zombie - Graham is a young white male who wears zombie make-up and tattered clothes, who can be found at the corner of Vinewood Boulevard.
Griff - He is found at Larry's RV Sales on Route 68 in Harmony.
Impotent Rage cosplayer - Impotent Rage is a cosplay of the cartoon superhero Impotent Rage, from the in-game television show of the same name. He can be found in front of the Hardcore Comic Store on Eclipse Boulevard.
Jane - She can be encountered in front of the fountain at the Rockford Hills City Hall, near Carcer Way in Rockford Hills. She appears to be a stereotypical "new age" soapboxer.
Jesco White - In story mode an easter egg featuring him tapdancing to the song "If You Wanna Get To Heaven" can be found across the Alamo Sea from Sandy Shores, he spawns in front of a house directly behind the first boat dock one passes. This occurrence only happens in single player. - Not needed
Jesse/Jesus - Jesse is a laid back bearded man that can be interacted with at Del Perro Pier.
Mani - Mani is a Mexican man who appears in the Alta neighborhood, near the corner of Elgin and Hawick Avenues, by a gazebo in a courtyard filled with food shacks and bordered by two Mexican restaurants.
Mime - Can be found performing in the Prosperity Street Promenade in Del Perro. - Not needed
Pamela Drake -She can be found trying to recapture her past glory - trying to attract the attention of movie moguls and the like - by prowling Vinewood's famous Vinewood Boulevard, reciting lines from movies of a bygone era.
Jerome - Jerome is a minor character in Grand Theft Auto V, appearing as a soapboxer. Jerome can be found in Dutch London Street in Rancho. He is an Afro-American priest that will be reciting his beliefs, saying that people are filthy sinners and that they all are going to die in a painful and horrible death, unless they join him in paradise.