Wang Dang Atomic Tango is a quest provided by James Garret in the Atomic Wrangler (located in Freeside). He needs three additional providers for prostitution services: A suave talker, a sexbot, and a ghoul cowboy.
You will receive a cash reward for each recruit, which starts at 50 caps. A successful barter check can increase the reward.
To gain a lead about the sexbot, head to Mick and Ralph's and speak to Ralph. He will tell you to try Cerulean Robotics, and that you'll need a holotape to program it. You can program it yourself if you have 60 science, while Ralph will offer to make one for 150 caps. You can get it down to 100 caps with 35 speech, or get it for free if you have 50 speech.
To reach Cerulean Robotics, head to the intermediate gate in Freeside, and take the north west path.
Inside you will find the robot, which is controlled by a terminal which requires 50 science to hack. If you do not have 50 science, you can find a terminal access card. To find the card, head into the room right from the entrance. Between the couches you will find a skeleton with the Cerulean Robotics key in its hand. This unlocks a tool cabinet in the north of the building which holds the terminal access card.
You will have the opportunity to "test" Fisto before sending him to the Atomic Wrangler, and the screen will go black, you will hear a drilling, and afterwards you will complain of numb legs, which is normal.
In addition, there is a bug with older versions of New Vegas. You may continuously converse with Fisto after recruitment to receive an infinite supply of caps. It will take a while at 10 caps per speech, but is useful for some cases.
There are two people you can hire for the suave talker, Sandiago and Old Ben.
Sandiago is located in the squatter camp in the south-east corner of Freeside, across from Mick and Ralph's. He can be recruited without difficulty. However, choosing him causes a bug with another quest, Debt Collector, where dialog options to talk about the debt might not be available.
You may also speak with Old Ben, located near the gate to the Strip. You need at least 50 speech, or either the Confirmed Bachelor or Black Widow perk. You cannot recruit both, and if you try to hire Old Ben after Sandiago, Ben will turn up at the Atomic Wrangler but you will not gain caps for recruiting him, nor can you use his services.
The ghoul cowboy is Beatrix Russell, located in the Old Morman Fort, in Freeside. You will need a barter or speech skill of at least 35 to recruit Beatrix, or a bottle of Absinthe to bribe her with. The bottle is rare, but is sometimes found on travelling merchants, but one can be found in the Lucky 38 Cocktail Lounge, and one is given as an award for winning 3750 caps at the Atomic Wrangler.
Once Beatrix is recruited, you can head back to Garrett.