I assume that you can attain orgasm when masturbating, but not when engaged in sex with your partner. Are you only having intercourse? Vagina-to-penis intercourse gives only indirect clitoral stimulation, and your clitoris has a central role in elevating feelings of sexual tension. To reach orgasm during intercourse, many women need direct stimulation both before and during penetration. You can try using your own hands during intercourse, or guiding your boyfriend's hands to rub your clitoris during sex. You can also try a variety of positions where your clitoris might get further stimulated. The woman-on-top position has more potential for clitoral stimulation than the missionary position for instance. You can also request direct oral or manual stimulation from your boyfriend before, after or instead of intercourse, verbally letting him know what turns you on the most.

If it's more a matter of whether or not you're allowing yourself to have an orgasm, rather than the physical manipulations to get there.

Regards
Dr Elna McIntosh