Consent is consent, no means no, all things that we learned growing up but people seem to forget, conveniently, while they're "in the moment."
The biggest of all those being, "I don't want you to orgasm in me" and then the male does so anyways—this is sexual assault.
You don't get to decide for a female that she has you inside of her and can potentially get her pregnant. We all know the "pull out" method isn't foolproof, but at least you're respecting her wishes when you do so.
Saying you forgot, emitting "oops" and moving on with your day, isn't acceptable at all. You need to realize that what you're doing is wrong. This goes for anything that involves another person's body. If she says not to touch her butt, and you do, you are violating her trust, and you're assaulting her sexually. This isn't cute behavior, and we need to stop letting it slide, there's a reason someone doesn't want to be touched.
For a lot of people, not wanting to be touched comes from some abuse they received in the past, and she shouldn't have to tell you a story about it for you to understand that it's not your place to decide.