Imagnine you are being sucked into a TV, what sound would it make?
Or what if you had just teleported into a zone and somebody asked you about this sound design technique.
Waves dashing themselves against rocks, reversed, pitched down, slowed to half and gradually sped up to double as you get closer to the screen.
I'd add a normal kind of 'sucking' sound like a reversed plunger or something similar, and add some kind of electronic sound as well, maybe an automated low-pass filter sweep on a White Noise sample?
Cheers
Use a mouth! Actually any kind of reverse can be a suction. After you reverse, add reverb or fx delay and reverse again!