rub one's hands
Experience or exhibit pleased anticipation or self-satisfaction, as in The owner rubbed his hands as the customer picked out item after item. This metaphoric term alludes to the actual rubbing together of one's hands to express pleasure.
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.