How we cite our quotes:
Quote #1
"The black stood stripped to the waist behind the tent and as the juggler turned with a sweep of his arm the girl gave him a shove and he leaped from the tent and strode about with strange posturings under the lapsing flare of the torches" (7.185).
John Jackson has been having sex with the daughter of a juggler behind the juggler's back. Though it's not like the juggler could do anything about it even if he knew. He's more or less at the mercy of Glanton and his men.
Quote #2
"Standing just within the door of a foul saloon with his eyes shifting under the brim of the hat he wore and the light from a wallsconce on the side of his face he was taken for a male whore and set up to drinks and then shown the rear of the premises" (22.64).
The kid has no way of making money once Glanton's gang is killed, so he wanders the deserts and often gets mistaken for a male prostitute. It's not really clear whether he takes any men up on their offers to pay him for sex.
Quote #3
"Garishly clad whores were going out through a door at the rear of the premises" (23.132).
In the Wild West, the police weren't too keen on enforcing the laws against prostitution. In fact, most of the time there were no police at all. So yeah, stuff like sex for money was pretty darn common.