My guess is that she knew all along that her pussy was exposed and she wanted those guys to get an eye full, she was feeling horny and playful, that's all
That goes without saying she was as horny as fuck, that's why she was showing her pussy to you and the other guys, hoping you would all fuck her, I'd bet while you were fucking her, all the time she would have been wishing it was the other guy tag-teaming her