Isn't that normal? That's seme/top magic. The inside of any transportation vehicle they own naturally expands, without the exterior expanding. It's all powered by their "love"(lust) and need to comfortably take care (devour) their beloved ⁄(⁄ ⁄·⁄ω⁄·⁄ ⁄)⁄
I noticed the size of the carrige is abnormally large inside compared to the outside ε=ε=(ノ≧∇≦)ノ