Grease someone's palm
Grease someone's palm (English) — To pay a bribe (a kickback), to make a payment to obtain favourable results or influence. Like unions, or a lobbyist greasing the palm of a politician. Although bribery denotes a crime, criminal activity greasing someone's palm may be no more than asking for, or even doing favours for someone that you expect ease in actions to be taken or perhaps a position to occupy (a promotion or power).
Greasing a palm afford something to 'slip through' someone's grip and let something just slide. Let it occur without incident.