Definitions inside my tiny mind:
Cum kiss: after a blow job to completion, the BJ giver keeps the cum in their mouth and then kisses the BJ receiver. Point being to give the kiss an accent in taste and experience. Load split mostly evenly for swallowing or dribbling down chins.
Snowball: after a blowjob to completion, the BJ giver then passes the load to the receiver (or third party) trying to get the entire content of their mouth into the receiver. This then repeats from party to party such that the volume "snowballs" due to saliva addition.
Now, there will be many who say who cares what you call it? But knowing what you want and how to communicate it is important, if you want to get what you want.
Personally, sticking to my definitions, I love cum kisses, but snowballing edges into spit play which I am ambivalent about.
Do you have different takes and/or what other terms are used for cum play?