He takes so long to finish!!

So me and my boyfriend are both 17 and we’ve been together for about a month. We don’t do stuff that often but when we do it’s really goodd. The only thing is tho he takes so long to cum, like I haven’t actually made him cum yet!! I’m not one to toot my own horn, but I know I’m at least decent at blowjobs, he’s even said to his friends in front of me that I was good and every other boy I’ve done stuff with have said I’ve been really good. But I get so tired from doing it and he’s so sweet so he just said to stop but I want to please him. He’s really respectful and he’s said that for the both of us he wanted to wait before we have sex because he didn’t want me to feel like I’m being used. He’s honestly the most amazing boy everrr and I just want to fully satisfy him!! So ladiesss if you have any tricks that may help me please let me know!!