It does depend on what society considers appropriate to do in public.
If for some reason they're not OK with sex in public, then I'm presenting them to the crowd in some sort of loincloth or thong, then we strip them. Either that or they go to their whipping stark naked. It's generally understood that they were raped in prison. They may have dried come on their inner thighs. Or they may still be dripping if we raped them just before the execution. They're going to get whipped. We can put them on the whipping post and then strip them. But seriously, it's 2024. Attitudes towards nudity were a bit more restrictive in the 90s and early oughts. These days, you should probably figure on being naked for longer.
If it's going to be a public rape, I'd prefer the girls to be wearing something. They can either strip or we can strip them. We've got restraints as well! Usually I tell them I will make things go a bit easier for them if they cooperate. OK, for this to work, you really have to keep your word. There's good deception and there's bad deception. Good deception is when we've led a girl to her crucifixion site, then we wrestle her to the ground, and she probably pees herself, and then we tell her OK, your sentence is suspended, but you had better be good from now on, OK? Or else you know what is going to happen to you. OK, you can go now! Bad deception is if you tell a girl she'll get some mercy and then you deny her. Don't do that. Or at least, I don't do that. If she has absolutely zero chance at mercy, I let her know.
There's two ways for me to enjoy this. One is I can get the girls to cooperate. Sexually, I mean. The other way is that me and my men can fuck their brains out, then we can wring every last scream out of them and savor their futile struggles as we nail them to the cross.