쪼물락 is drived from verb 쪼물락거리다. Actually '쪼물락거리다' is a kind of dialect of '조물락거리다'. If you find out '조물락거리다' in a dictionary, you can find out the meaning such as "finger (a toy), fumble with[at]". You can think 쪼물락 means fumbling with[at] or fingering something.