HSK 7-9
蹭
cèng动
to rub against; to walk slowly; (coll.) to freeload
小猫在主人腿边来回蹭。
Xiǎo māo zài zhǔ rén tuǐ biān lái huí cèng.
The kitten rubbed back and forth against its owner's leg.
Say it
Hold the button, say it, then let go.
Also free:
Appears across levels (7-9) in the HSK 3.0 word list.