How do I show affection to my boyfriend without kissing him?

My boyfriend and I are freshmen in high school, and yes, I know, we’re too young, but to be fair, we were friends first and then he later on told me how he felt and told him I felt the same way. Now, I do know that we are really young, which is why I am refraining on kissing. He’s kind of shy, but he used to kiss his past girlfriends. We’ve tried to hold hands and lean on each others shoulders but we have a group of friends that sits with us at lunch, (lunch is the only period we have together,) which is fine because they’re are friends, but its kind of embarrassing because every time we try to hold hands or something, our one friend starts freaking out because she is very easily over-excited, (she doesn’t do it on purpose or to embarrass us, its just her personality.) I have told him that I don’t want to kiss because it will lose its meaning and that we are really young, and he completely respects that, but everyday we see other people kissing and he just looks at them and then looks at me and then back at them and then very lightly sighs. I do care about him but I don’t know how to show it. Thanks for reading.