I would say no to either scenario. No thank you. 
Sometimes a girl will allow a semi-3 way with a girl that is slightly less hot... to keep her guy attached but fulfill some fantasy while they still are present to keep things from going too far. Such as, "You do me while I make out with her, you can feel on her, but please no penetration on her" or something like that. It's a safety valve. It prevents a guy from panicking with "I'll never touch another woman again!!!!" and gives them a hot, fairly safe fantasy. Nobody getting preggo, nobody falling in love... just fast and rarely repeated with that person. The moment it becomes "Thursday night 3-way action", someone is going to end up texting each other on Friday and chatting all weekend...