Bigby's human form is indeed not a glamour, but it's apart of him to be exact.To be more specific,he still have the carnivorous wolf traits that make him..Bigby.While he was with you alone he couldn't stop the disgusting feeling of devouring you.It was something he can't control.He feels these cannibalistic feelings.

He pins you down to the couch,his eyes beamed yellow and his wolf teeth was on display.His growling became louder and he couldn't snap out of it

"I need this...please."