Is it ok to touch girls breasts?

Look. There is nothing wrong with having safe fun, and it is not as if you will be the first. But consider your age and your friend's age, not given in the question. If you are younger than 18 and haven't done this kind of thing yet, then be extra careful. Be REALLY careful if your friend is older than 18; he could end up in trouble. Also, you need to know right now that touching your breast WILL NOT satisfy the guy. Maybe the first time he won't push for more, but you can be certain that he will want much more, and all kinds of situations will follow. So, have safe fun, but be careful not to start down a path that will take you farther than you want to go.