You state that you feel self-conscious. For me, that was my normal sexual state for years. And yes, I rarely had an orgasm with another. Somewhere along the way I quit feeling that way, starting feeling more comfortable with myself and recognized that I was beautiful - if only to myself and God. And the orgasms began to come easier.

Perhaps as the self-conscious feelings abate, you'll be more able to cum. Remind yourself that if you were not a lovely person, your Dom wouldn't be with you. Most of all, love yourself.