chum up

verb4

1. •
   (informal) To be friendly toward (with or to) someone, especially in an ingratiating way; to form a friendship (with).

   • I chummed up with a few of my new work colleagues.
2. •
   To apply chum to water as bait.
3. •
   To render a situation frenzied and confusing.
4. •
   (slang, no longer used) To initiate (a new prisoner) through a ritual involving beating him with sticks and swords, accompanied by music, to extort money from him.

   • They have a practice of “chumming up” a new fellow-prisoner—beating him with old swords and staves kept in the prison for the purpose, to exact a fee of a half-crown. — 1844