搓 describes a back-and-forth rubbing motion, typically with hands. Common collocations: 搓手 (rub hands), 搓澡 (scrub the body while bathing), 搓麻将 (play mahjong).
memory
The hand radical 扌 on the left shows it's a hand action. Picture rubbing your palms together for warmth.
Left-side hand radical, the three-stroke side form of 手. Indexes 搓 in the vast family of hand-action verbs alongside 打 to hit, 拉 to pull, 抓 to grab - all things palms and fingers do. Here it marks rubbing as a deliberate handwork motion.
Right side 差 supplies the sound: chā shifted to cuō, a regular ch- to c- alternation. 差 itself shows hands working unevenly, which lends a faint flavour of the back-and-forth motion of rubbing palms together. Same phonetic underlies 搽 to apply (powder).
