下手で対戦者の廻しを引き寄せて対戦者を投げます。
また、対戦者の上手投げを打ち消す効果もあります。

Sumo wrestler draw a mawashi of the opponent with Shitate and throw the opponent.
In addition, there is the effect to deny uwatenage of the opponent.

追申
上手は、対戦者の腕の上になった腕のこと。
下手は、対戦者の腕の下になった腕のことです。
P.S.
The Uwate is the arm which I became on an arm of the opponent.
The Shitate is the arm which I became under an arm of the opponent.