Get it? She's trying to fuse with Rose the same way Rubies fuse together, by standing on top of each other, and of course it doesn't work. It's like two inexperienced lesbians trying to do it missionary style.

Oooo, the thirsty servant girl forcing herself on her Diamond master. How bold! And I guess non-consensual fusion just looks like awkward cheerleading maneuvers.

I'd also make a joke about Pearl getting a nice eyeful, but chances are Rose probably looks like a barbie doll down there. Gotta wait until she's craving that sweet human meat.