The fact is that you can say no at any given time. It is your body and your choice to make. When someone says no it is a final statement. There should be no question about whether they want to be touched or not.
Let me make this clear. At no point in time is it too late to say no. It does not matter if it is down to the last minute. Nothing that happens after you say the word no is being done with your consent. If someone chooses to force the issue, after being denied what they want, is not only committing a moral violation, but may also be breaking the law.
For the same reason, it is not nice to lead someone on. It is understandable if someone changes their mind at the last minute. After all, there are many reasons why a person would continue with something that they do not want to do, the least of which is peer pressure. Sometimes however, making the right choice is not the easy choice to make.
The right to say no places you in total control of your own destiny not someone else. There is no reason for something to happen to your body that you do not want to happen. Yes, someone may get angry, but if you were being touched out of love then you will still be loved after you say no. The right to say no is not gender specific. So if either of you want to stop respect that.