Well, to be honest if he doesn't want to do it chances are he will never do it...however...perhaps he just needs lots of enticing...more than words that is, how about trying to "seduce" him so to speak.

Dress up in something sexy, and have him sit down on the bed, chair, whatever and put on a little show for him. A slow strip tease, caressing your whole body, telling him how good it feels...how good he makes you feel...touch your breasts, your thighs, your pussy...then bend over and play with your ass. Caress your buttocks, pry them apart and display yourself to him...touch your anus...rub it...tell him how incredible it feels...slide a finger inside of yourself (after generous lube of course)...maybe he will get the message then...if not well...I am out of ideas

Maybe your boyfriend and yourself need to really talk about your intimacy together since you say he is not willing to take the reins and try anything new. Variety is the spice of life, and if he is not willing to explore new horizons with you...this may leave you very frustrated, and it sounds like you are approaching that point already. Well, I wish you luck, take care!

__________________
"And as we all play parts of tomorrow, some ways will work and other ways we'll play. And I know we can't all stay here forever, so I'll write, my words on the face of today...and then they'll paint it" - Shannon Hoon