It’s okay to say “no” if you change your mind. We allow you to change majors and change direction and change clothes, with no repercussions other than possibly wasted time. If his touch is too forceful and his breath too hot and his weight too much, you are not bound to your previous decision. If your mimd is screaming and your nerves are sizzling, they are as valid then and now as they were five minutes ago, when you were saying yes.
It’s okay to say “no” if you were flirting. Batted eyelashes and sly smirks and witty words do not form a map to your uncharted territory. Your playfulness does not relieve them of their self control. Your allure does not diminish their responsibility to be respectful. The only path you led them on is that of the unknown, of which the rules of the road still apply.
It’s okay to say “no” if you’re unsure.
It’s okay to say “no” if you’re embarrassed.
It’s okay to say “no” when they tell you it isn’t okay to say “no.”