This is a fundamental rule in judo: if you want your opponent to come forward, push them backward, and if you want your opponent to go backward, pull them towards you.
This is a basic reflex in human beings -and all mammals-. Evolution has made us this way, when we encounter a sudden dangerous force, our reflex is to go against it without thinking.
This reflex has kept us safe for millions of years. Judo and other grappling arts are famous for exploiting this “loophole”.
Now back to Yoko wakare, push your opponent repeatedly until you feel them pushing back, then use their forward momentum and surprise them with a Yoko wakare.