can't orgasm

my bf and I have some pretty good sex and I really have no complaints but I've never orgasmed while having sex with him :( . I really want to because there will be times when we're both going at it with each other and he is just pounding me and it will feel sooo good ( sorry if that was tmi) But I won't orgasm.. I cum but don't get the pulsating feel that I reeeeally wanna have. I wish we could finish at the same time. so how do I make myself orgasm when we have sex? any tips?