My butt’s too big for meditation

I’ve been working to build the habit of meditation, but as I continue to practice there is one thing I always realize… my butt is too big for this! I sit criss-cross-applesauce (I have kids, what did you expect me to call it?) and allow myself to gently sink further into the ground. I feel very grounded, until my rear feels like it’s sinking more than the rest of me. I can’t lean forward and still focus my breath the way I want so end up tensing my legs which ruins relaxing the muscles. So basically I just consistently feel like I’m falling backwards. Maybe my imagination is too strong, maybe my over sensitive brain is confused, or maybe I just have a giant ass. Regardless, it seems strange to complain that my butt “sinks” further than my legs into solid flooring inside a building. But those are the joys of beginner meditation, right? Or is that just me?