I'm currently working on a short film adaptation of a children's book called 'There's a Hippopotamus on the Roof Eating Cake' (Here's a link to a teaser if you're interested: http://vimeo.com/9576401)
Very simply put it is about a girl and her relationship with an imaginary hippo that lives on her roof.
Anyway there is one scene where the hippo falls off the roof and he and the girl have an intimate moment, where she tends to his cut (from falling) and snuggles up to him.
I've been trying to create a huge, deep, warm breathing sound (and a general 'rumbling' presence) for the hippo during this scene, but I'm having trouble. I've tried playing with the pitch of my own breathing, placing the mic right next to my lungs and processing animal sounds (admit-ably I don't have access to very good recordings) but I can't get the depth and weight that I'm after.
I love Randy Thom's work on 'How to Train Your Dragon' (the sounds when Hiccup finds Night Fury in the woods are amazing!) and obviously Avatar, LOTR etc are an inspiration.
So if anyone had any insight on how to achieve those sounds I'd be very happy!