Tips to Cumming during Sex?

I’ve always had trouble cumming during sex, and I’ve been with my boyfriend for almost three years now and have yet to cum on his dick (I want to do bad😂). It’s not that he isn’t good bc he knows how to use his dick 😂, it’s just a struggle with “letting loose”. I’ve gotten super close before, but I’m too scared I’ll make a mess when I cum. Any tips to “letting loose” and just cumming?? My bf is spending the night tonight and I don’t wanna go to sleep until I’ve cummed on his dick lol