the anti-grav glitch is achieved by having most of your character above water while still having the bottom of their hitbox slightly in the water, and then spam freezing/unfreezing the water until the glitch is performed. it also appears that the second player's location also affects whether the trick works or not though so while consistent, it is very dependent on that factor. you have to play around with it until you get it to work. you can watch our pb video to get a visual understanding of how we perform the glitch

my friend and I have been playing degrees of separation through steams remote play function and we havent been able to replicate the jump boosting. we couldn't do it in online co-op either. curious if anyone has looked into this any further since 4 months ago. we have also been able to replicate the anti gravity glitch in the falling towers level only and it can be used to get a few scarves faster interestingly enough!