You sometimes get the impression that authors don't even KNOW there are other things couples can do together. But of course they must know, because teens themselves know (I hope), and authors were once teens. So why don't we see these lower-risk, still-super-exciting intimate activities more in novels? I have to figure it's because writers are squeamish: they feel it's somehow too graphic to sketch out, say, manual sex or oral sex. I say it's doing a disservice to young readers to dodge the issue, however, because what if teens honestly do need a reminder that you can enjoy your significant other without putting yourselves at the highest possible risk?
In my teen books, I dare to enter that territory. Teens get naked together and get satisfaction without risking pregnancy or (most of the common) STD's.* Some of my teen characters are virgins, and some aren't, but all have sexual interests and sexual thoughts, because I think guilt-tripping kids for their natural thoughts is an even more grievous disservice. (I'm looking at you, churches.) In a word, I want to be sex-positive. We don't need the shame, and we don't need the clueless danger. We CAN achieve a balance of sex that's both fun and safe--even for teenagers. Especially for teenagers.
*Of course, you can get some STD's from skin-to-skin contact, or oral sex, but then you can get a truly nasty cold from shaking someone's hand. Big world, lot of microbes; take your risks as you will.