Dating you made him realize he couldn't care less about arbitrary rules, he just likes you, and he loves the way you look together.
The spider has both of you reclining away from one another, mitigating any vertical distance that might typically separate your faces; as in cross buttocks, the only thing that matters here is your genital apex.
He helps by supporting some of your weight and grabbing your hips or thighs while he rises to meet each thrust.
With shorter girls, you might need to do some squats to get at lip-level.