Ki Suppression is...?

[SirAlex09]

The Daizenshuu 7 notes that Mr. Popo can nullify his presence ("erase his own ki") and that he used this ability while training Goku.
In Chapter 164, Mr. Popo stated that he learned much from Kami, so it make senses that Kami possesses this ability too.
Also in Chapter 164, Mr. Popo stilled his heart and mind to the point that Goku found it difficult to sense his Ki and attempted to teach Goku this ability.
Both the manga (Chapter 165) and the Daizenshuu 2 make note of Goku's training involving sharpening his mind and his spirit.

And again, this is not the same as suppressing their ki because they maintain their level of strength.

I agree. If they surpressed their Ki , they wouldn't be that fast