turn on and foreplay

my boyfriend and i have been fooling around for a little less than a year now, and started having sex probably half a year ago. i've only felt super, super turned on when we were having sex a couple times and i don't know how to tell him i want to do more foreplay. i reach an orgasm by masturbation almost every time so i know i'm capable of doing it, but i've faked multiple orgasms and have never orgasmed with him. i don't feel turned on enough before we get down to the nitty gritty but he gets horny right away. anyone have advice on what foreplay we can do to get more turned on, or how to tell my partner i need more time before we actually start doing it to do foreplay?