The sandals Oola wore as Jabba's slave, were cheaply made and left her feet sore after each dance performance. They were strapped tightly to her ankles by thin strings and the soles were made of raw bantha hide that possessed little traction. This made it easier for Jabba to pull Oola back to his throne after a dance, the lack of traction making it difficult for Oola to plant her feet and resist her master.
After a dance session for Jabba and his goons, her feet would get sweaty and smelly. This added to her humiliation, and the arousal of Jabba and the courtiers.