Through the nose, exhale slowly with a soft 'hmm', then inhale sharply (also through the nose), producing a 'hmm-hp!' sound. This is a squeakup. Looks and sounds similar to a hiccup, and is extreme happiness in sound form. It is often accompanied by a facial expression of glee, and is highly contagious.
When Emilio squeakupped in delight, Paula couldn't help but mimic.