Not always the case blahblah,
It is true that some may turn out to be shy back in the room, usually known as the 'towel wearers' but as Figjam has pointed out to you, negotiation is the key here.
As he stated, talk with the mamasan/papasan and tell them what it is you are after, they heard it all before and will not be surprised if you enquire if they have 2 girls that will be happy to do a lesbian show for you or whatever.
When you speak to the girls in person, tell them what you want and that you don't want girls that will be shy in front of each other, while there are shy girls in the bars, there are also girls that act quite slutty and would be happy to cater for your fantasies.
Happy hunting, which is all part of the fun.
