Just imagine you are dust and your partner is a Dyson vacuum cleaner.
1-2-3, at 3 he pulls you and you are vacuumed into the Dyson. If these action is harmonically done, this will be a clean and quick Gyakuzuki that your partner can't react quickly.
If not harmonically done this would be a typical Godzilla Gyakuzuki!
Practing the fine Karate which gives chances to us, who are not physically stronger.