Kiss someone's ass/arse/butt
Meanings of "Kiss someone's ass/arse/..."
1. To be subservient to someone. To be available and act on any need or desire of theirs. Playing a role of a slave without gain or consideration
2. To attempt to, to find favour with a person(s) in order to achieve some position, title, better conditions, perception with them.
3. A figurative vulgar imparative given when someone angers an individual. "Kiss my ass!"