Is it haram to watch sex dolls during Ramadan? Is sex ed haram during fasting? In school they teach you about sex ed and this year in year 12 I was fasting but they did a sex education lecture
First of all, if your act is for learning like you are studying some topic or it is necessary for you to study this like you are in college or university where it is going to be taught then it is not invalid. And if you go to follow the islamic rule in a strict manner then its depend on your strong belief. If your strong belief is that it is invalid action then that is invalid. Never go for that. Strong belief is a term in islam that means what your inner self says about some thing. The inner self is believed to tell you the right way always.
I think, if you believe those informations are important for you at the moment it's permissible to attend to classes. However, if you think there are unnecessary detailed graphics with these dolls that emerges some urges in you it's not permissible to watch it (I don't know what they show you during these classes ). You don't have to be learning everything in the public right now, since we as muslims already wait for marriage for sexual intercourse ( I'm not against sex ed, just against exaggerating it)
Addition to that, if something like this is Haram it will be always Haram regardless of you being fasting or not. But sometimes if education is necessary, talking about these things is permissible, otherwise it's not good to talk about these matters in the public anyways.