Llama eater

The one that wears 'the pants' in the relationship; takes control / takes the powerful role while the other is quiet and obedient. The llama eater 'EATS' the llama.

'YO, Alexia is SUCH a llama eater, look at her chompin' on Gray's head.'
'I disagree, Gray is a feirce jaguar, he ain't no llama. He'd eat Alexia in a heartbeat.'