It appears that you are pushing up and out, using the legs, arms, chest etc right? You indicated that once your partner's center is physically above yours he is floating. Clearly once he is above you, he is much easier to manipulate.
When I am referring to floating, you don't need to physically change the difference in height between you and your partner to be under them. You want to redirect their force down to make your partner go up. I discussed part of one way to do this with my shoulder video post.