>The embodiment of Rose's love and Pearl's thirst
>Has twice the bedroom eyes

Well played, animators.

I think the fact that Pearl's eyes are larger represents how huge her thirst is.

Or at the very least, how much she tries to force the relationship (or lack there of). It is all about what Pearl wants and the image she has for it.

Of course, playing the 'whose is what now?' is always a bit fuzzy with fusions. The lower eyes kind of look like they are sneering with the 80's high school mean girl taunt she is planning to drop once she unfuses.