Remember that we never see this stuff on movies/TV/advertising and no-one really talks to us about it. It’s hard to know if we haven’t been taught and it’s also hard when popular culture tries to tell us that it’s not important. Lots of people DO ask and hopefully we’ll see it more in the movies soon.
Then you don’t kiss them and let them know that you respect their decision. Remember that consent needs to be gained freely, willingly and enthusiastically. It is SO important that we respect people’s decisions about their bodies and relationships. In this case, you could talk to them about it and ask if they want to talk more about it. They might not and that’s okay. You might like to check in with them again down the track (in a few weeks not in a few hours).
If a friend shares something with other people that you shared in confidence with them, I’d suggest having a talk to them about what being a good friend means to you/them. Being trustworthy is an important part of being a friend. Often in schools people talk a LOT about who likes who and who asked out who. Remember that you can’t believe everything you hear and thing about the impact of the gossip on the person it is about.
There’s no easy answer for this because everyone person is different. Being a teenager can be one of the best times in your life because you have lots of opportunities but it can also be confusing and scary. There’s no rule book on how to act – but being respectful is a great start.