On a serious note, as someone who considers himself a Christian I think all premarital sex is immoral, but if I'm judging by general modern sexual morality, I suppose its complicated.
The deception angle is weird because unlike trannies dressing as women to trick drunk men, you are a man and the pooner is seeking men, is there any substantive difference between how a gay man would fuck a Pooner or how a straight man would fuck a pooner? Other than the Pooners fetishised view of gay men through the lense of Yaoi? I couldn't say, I've never had gay sex nor would I touch a pooner with a ten foot stick.
We could also talk about how confused the Pooner's definition of "straightness" would be, considering she's almost definitely a true believer in Alphabet-people ideology, whose to say you're straight and not a poonersexual or whatever? Or even if she'd care? I'm assuming you're not getting into a committed relationship with her and are just having a one-night stand, because a committed relationship completely changes the dynamics of the question.
Also, to clarify my actual position, if you do this you're weird and creepy, even if you don't fall under the category of rapist you're getting awfully close to one, considering the level of deception this would require and the fact that they're almost definitely severely mentally ill.
TL;DR All sex outside marriage is immoral and leads to bullshit like this, the west has fallen billions must die.
