If you want to partake of such services in Fallout: New Vegas, you've got to ask nicely, and they have to like you and give consent. Even the robot.
My favorite moments from Fallout 3 came out of a collaboration between the creative output of the designers and my own imagination. The game set up situations in which moral decision was entirely in the hands of the player: help the slavers or fight them, save the villagers or exploit them, the good of the many or the good of you. In one quest I recovered a pristine, powerful rifle that belonged to Abraham Lincoln. I held onto this gun, not using it but hoarding ammunition, until I’d leveled up to the point where I felt strong enough to take on the slaver camp head on. I attacked at night, and the only weapon that I used was Lincoln’s rifle. I freed the slaves and literally blew the head off the slaver bastards. The game gave me the requisite XP and rewards, but the greatest pleasure I got from the whole experience was the symbolism that I’d laid upon it.
For all it’s bugginess and slightly outdated graphics and stiff animations, this is the area where Fallout: New Vegas shines most brightly, presenting you with compelling moral quandaries and letting you make decisions. Having added a nifty Reputation system into this game, the consequences of those decisions now vary across the wasteland. Some will love you, while others will hate you for what you do, as is the way in the real world, where the moral landscape is a jumbled mass of prejudices, preferences, and pretensions. Even so, the game’s options usually come down to questions that the vast majority of people would agree upon about what is moral and what is immoral (killing innocents for your own gain is bad, killing psychopathic killers is good). However, there are a few exceptional set-ups where morality is much less clear, and the ones that fascinated me the most were a pair of quests centered around sex slavery and prostitution.