How can wewe tell the gender of a mochi? Can anyone explain the old man's method?

Mochi fans, anyone there who can explain it? I already ilitumwa this one on the Hetalia FC but nobody answered it yet.

*see the strip* (from the Omochi Omochi strip: link)

(follow the panel from left to right:

If wewe can't read what they're saying..

panel I: Estonia asked how can the gender be identified.
panel II: The old man has a method. I don't know what the old man exactly alisema because it's written in hiragana but he's probably asking Mochirisu if he can leave the Teddy kubeba with him.
panel III: Mochirisu told the old man to leave it there.)

then....

Tsunderely staring at the teddy bear, the adorable little thing went on blushing then jumped towards the teddy.


How does it work? What's Mochirisu gender then, based on that method?