I guest the easiest way to do it will be to go practical with actual balloons stuffed into clothes - with a good text or speech (plenty of inspiration here) you can have a really nice video. Most of the vids within inflation / expansion community that have access to actual models work much better with actual balloons and inflatables than videos sfx. Don't worry if it look fake - it's not something that exist in real life anyway, so if you act it right and are playful about it it'll work.
Otherwise I'm sure you have a bicycle or party balloon or yoga ball pump laying around the house. Include it and you'll have a lot of fetish fuel lighted up! ;)
I have had my own website since 2002. Focusing on fetishes. I want SO BADLY to put a body inflation video up on my site. I see other models doing this, but I can not ( FOR THE LIFE OF ME) seem to figure out HOW to do this effect myself in PhotoShop or IMovie either one.
Can anyone help? I would be more than happy to work with someone to make it happen. Maybe I can shoot the video and you can edit? ~please! can anyone help?~