Jaden Smith Packs on PDA at 'Suicide Squad' Premiere

Jaden Smith really enjoyed his dad's "Suicide Squad" premiere -- not because of the movie, but because he was all over his girlfriend all night.

Jaden was hugging, sucking face and holding hands with Sarah Snyder during the NYC event.

This is just what they do ... we've seen Jaden and Sarah doing this same routine before out in the streets of NYC.

They're young.