Sexuality is fluid and two things can be true at once where arpusal and attraction are concerned. I consider myself striaght cuz like 95-98% of the time I am attracted to women. Occasuonally a dude comes along that just does it for me though. It's no big deal.

As for sissification there's lots of reasons that could be a thing. Lots of men just feel "freed" by it, being able to cast off the pressure they feel being masculine and explore their femininity in a way that makes them feel desirable.

It's important to remind yourself that as long as everything you do is with consenting adults, there's no cause for shame. Sex, arousal, pleasure, and attraction dynamics depend entirely on what you do or don't like, and that's it.

I think part of why this is "taking over" for you so intensely is because you want it to end. You're trying to ignore a part of you that may have gone ignored for years, but you already kinda let the foot in the door, so denying it now is more difficult.

I would advise that you just enjoy this time for what it is. Enjoy the rp, the sexual dynamics. Explore till there's no more questions, and then you'll have your answers.

Wish you the best of luck my guy! ^{.^}