What is rape?

I'm posting this here because I want the widest range of possible opinions.

Okay, here goes. I recently came across a thread on Reddit asking posters had they ever raped someone. Some of the responses made me re-evaluate my understanding of what rape is.

A few people seemed to think they had raped someone if they didn't have explicit verbal permission to continue but had done so anyway. The general consensus amongst female posters was that a man should always ask and never assume a woman wishes to progress things sexually even if she seems to respond/initiates. One man said that he is so concerned about accidentally raping a girl that he makes sure to pause before progressing to each sexual act and gain her express verbal consent to continue.

I am female myself and I found reading this quite
problematic. How can you have healthy sexual experiences if they are stunted/interrupted by this worry? I would be annoyed if a man kept stopping and saying ''do you wish to continue?''. It's a step away from drawing up a contract and getting the girl to sign it! I feel like people shouldn't have to worry about things like this. Maybe I am naive?

If a woman is responding favourably in a physical manner to sexual advances then it indicates consent to me and I think things get very problematic if a woman can say after that she didn't actually give verbal consent and so was effectively raped.

If I were in a situation where I didn't wish to continue I would say no and react unfavourably with my physical person. I find it surprising that some women don't say no if they don't want to have sex and that some men may feel like they are forcing women if they don't get verbal consent. Is that rape?

I am not for one second victim blaming. I think anyone that pins any blame on a rape victim is morally wrong to do so - but doesn't a victim have to actually indicate they don't want to have sex if things are heading that way? If she does then of course it is rape if this refusal is ignored. But can it be considered rape if the man doesn't receive any signal to indicate his attentions are unwanted and the woman has engaged in sexual behaviour with him?

Another thread on boards had me thinking about drunken sex and rape too. A significant number of people believed that when a man and a woman have drunken sex, the man has raped the woman because she was unable to consent. I found this line of thinking appalling.

I'm also wondering where the boundaries lie between assault and rape.

TL;DR Is it rape if a woman doesn't expressly say yes? Can a woman claim rape if she doesn't give a verbal/physical refusal?

Thoughts?