A question for the Dominatrixes

If I am currently seeing a Dominatrix, in an obvious pay for play situation. Would I be out of bounds to request the inclusion of two or more of her subs (should they be willing) in a scenario?
Would I be expected to pay for their inclusion?
Mistress to this point in our relationship has been very open to my suggestions, and even steered our sessions into areas I dared not even dream I'd enjoy.
I guess my question really comes down to who pays?

That is something I would ask your Mistress, for it is all eventually up to her. I am a switch if I were to label myself. I allow myself the pleasure of being in charge and I also enjoy being submissive. In a mfm situation for me, everyone donated less than what they would usually. But for her, she may do things different. If her other subs want to play as well she may do the same thing. Your mistress seems open enough, don't be scared to venture out and ask. You may very well be rewarded for it!!!

Thank you my dear

As a Sexual Sensual Mistress I adore adding another sub to the mix butt as she is a provider then it is a doubles playtime. Now if I'm bringing in a Bull it is normally free or a very low gift

Thank you Ms. Athens and Deja Tha Doll! This information has been very helpful.