Antonyms for the phrase "more back slapping" could include words like "criticism," "disapproval," "censure," "condemnation," or "rebuke." These words denote a negative evaluation of someone's actions, behavior or performance. Alternatively, words conveying neutrality or even detachment could be antonyms to "more back slapping" as well, such as "indifference," "apathy," or "disinterestedness." While "more back slapping" might suggest praise, affirmation or approval, its antonyms suggest the opposite - disapproval or detachment. It's important in communication to be aware of the different nuances involved in a phrase or word so that one can employ the right words in the right context.