forced laughter
唲 centers on forced, insincere laughter—the kind produced to flatter or appease rather than from genuine amusement.
唲 combines 口 (mouth) with 兒 (child), likely suggesting the sound or expression of a child's insincere or coaxing vocalization. The exact historical development is uncertain.
A mouth (口) beside a child (兒): picture a child forcing a laugh to get attention or avoid trouble, producing a strained, unnatural sound.
For ジ, imagine the forced laughter sounding like a sharp 'jee'—a strained, insincere giggle: jee -> ジ.