noun
double slap; forehand and backhand slap
A slap delivered with both the forehand and backhand in quick succession, often as a dramatic or comedic gesture.
彼は怒って相手に往復ビンタを食らわせた。
He got angry and gave his opponent a double slap.
漫画のシーンで、主人公が悪
In the manga, there is a scene where the protagonist gives the villain a forehand and backhand slap.