Ask both girls to join you
From Create Your Own Story
"Well, it wouldn't be fair to either of you if I only invited one of you, seeing how you two are best friends, I'll take you both home with me."
They giggle again, grinning widely at each other. You hear whispers, but are unable to understand what is being said. In the parking garage, back at your car, they both want to ride in the back.
"Is that alright with you?" They ask in unison.
