吮

shǔn yōng shì zhì

吮痈舐痔

kiss somebody's ass

shǔn nǎi

吮奶

suck milk

shǔn shǒu zhǐ

吮手指

suck one's fingers

shǔn rǔ

吮乳

suckle

dà duō shù hái zi dōu shǔn mǔ zhǐ dà le jiù hǎo le

大多数孩子都吮拇指，大了就好了。

Most children suck their thumbs but they grow out of it.