Well, that’s a bit problematic because how far do you plan on taking it? I completely understand not being ready for anything more and you should wait as long as you need, but if you tease him too much, you’re going to give your boyfriend a serious case of blue balls and that’s just mean. So until you’re ready to actually get him off, I would keep that kind of touching/teasing to a minimum.
You can massage him through his pants, cup him there, put your knee in between his legs while making out so it rubs against his crotch, straddle him so you can dry hump, etc.
But do this sparingly and not for more than a few seconds because he’s going to have a massive hard on if you do too much and then with no release, that sucks for him. If he does come, then it’s gonna be in his pants and that’s a sticky, gross mess for him and it doesn’t sound like you’re ready for him to be doing that either. So the best thing you can do to make it easier on your boyfriend (and your relationship) until you’re ready for more, is to avoid getting him too excited.
Keep kissing. Keep taking little steps that you feel comfortable with. But keep in mind that he’s a teenage boy with very little control over his body’s reactions so to be the best girlfriend you can be is to understand that and hold off on touching below the waist until you’re ready for more there. Don’t feel pressured to do anything for him. You’ll be ready when you’re ready and if he’s the kind of guy you want to be with, he’ll respect that.

