Um, I don't know about anyone else but if I'm masturbating then my door is closed and locked so this sort of thing doesn't happen.
And that is your answer ... Lock the door so it dont happen. And you no longer need to wonder what are you supposed to say to her. :P
My niece actually enjoys watching me or her dad play games from time to time. The fact that this game mostly doesn't have sex is the reason I leave my door open. That and so my cat has run of the apartment. Lol. So your answer is to just lock my door all the time because I spend, o much time playing (literally all day long)? Actually even all night as well sometimes.
The answer is always "inconveneice yourself" instead of just not wasting time and money with sensless pointless money wasting. In this case the pointless programming of someone wet dreams. As for why I say it doesn't belong, I already said it but ok I will again, simply because the first 2 games didn't have it and I see Baldur's Gate as a non-sex needed game. That's it. Simple as that. That is just my opinion. Lots of you obviously feel diferently. That's your opinion and I'm ok with that. I seriously don't see why most of you have such a problem with me having my own opinion. I've said it, I think 3 other times now maybe only 2, I am fine with sex in other games. I don't see an actual point in cartoon porn at all but I realize that some people enjoy it. Fine. Ok. I simply feel it has no place in Baldur's Gate. Romance? Ok I can understand that. The sex? I seriously see no point. As for the "skip it and don't worry about it. You don't miss anything"? Kinda true. This particular part you actually do have to worry about it. Yes you can kinda skip it. But you do have to go through it with the dialog. Because you're dealing with a drow. A female drow. Everyone probably knows by now that if you don't deal with female drow properly they get very pissed off and then evil things are certain to happen. So if you want to find out what can happen if you go along with her so she do0esn't get to pissy, you have to click certain options that are indeed sexual in the dialog options. Your simple "skip it" is only partially an answer.
Ok. Sorry. I would love some censor options, but this is too much, Man. The sex scenes are optional. They are not in your face. They don't just pop up like in some games. You have to literally agree to go to bed with someone to trigger them. If you are agreeing to sleep with Lae'zel and your niece walks in because you purposely chose to sleep with her, and your niece sees naughty bits, that's on you.
The most naughty creatures in the game that just spring up on you are Harpies. They are only half naked, and you mostly don't see them up close. The duergar are vulgar, but you can turn your volume down and turn off subtitles if your niece is in the area.
Again, I want censor options so we don't have to do this kind of stuff, but your arguments are a bit argumentative and unreasonable, imo. I don't know how else to say it.
To me, your argument is like a man going to a strip club and taking his niece with him and then getting mad because she is seeing poll dancing. You have to purposely choose to see naughty bits to see them in BG3. It is not by accident. If it was, I'd be right there with you in Larian's face saying "Please no. I won't be able to play this game again in good conscience."
The most argument we have is story elements mingled with naughty scenes and no non-sex romance unless it's with SH. That's about it.
And you no longer need to wonder what are you supposed to say to her. :P 
