I have had doubles before. Just double the price and you get both ladies. This is available almost everywhere if the schedules allow it.
The key is, are they really into each other along with you. They can't be too into each other while ignoring you too. Beside my one 1 experience it was sort of like a tag-team match where the one lady would be working on you while the other would sort of, take a break and kind of sit out. Then the off gal would tag back in. While nice, it was almost like the gal would do half the work and each would get the full money.
Only that 1 time was it a true 3-some experience and that was a long long time ago. Kind of spoiled me forever.