shake on

shake on (something)

To grasp someone's hand as a sign that both parties agree to or on something, such as a deal or arrangement. I'd like my lawyers to look over the details of the contract before we shake on it. After several months of negotiations, I think we're now ready to shake on the deal.
See also: on, shake
Farlex Dictionary of Idioms.

shake (hands) on something

to clasp and shake the hand of someone as a sign of agreement about something. The two people didn't sign a contract; they just shook hands on the terms of the agreement. I think it would be better to sign an agreement than just shake on it.
See also: on, shake
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs.

shake (hands) on it/on something

shake hands with somebody to show that you have made an agreement, a deal, etc: ‘OK, I’ll let the car go for $5 000.’ ‘Do you want to shake on it?’ Let’s shake on it.
See also: on, shake, something
Farlex Partner Idioms Dictionary

shake on

v.
To make some agreement binding by shaking hands: Our negotiations went well, and we soon shook on the deal. If you're satisfied with the arrangement, let's shake on it.
See also: on, shake
The American Heritage® Dictionary of Phrasal Verbs.
See also:
  • grease someone's palm/fist, to
  • cover
  • grab (someone or something) by the throat
  • grab someone by the throat
  • grab someone/something by the throat
  • get someone's dander up, to
  • help (someone) along
  • help along
  • die on (someone or something)
  • die on someone