My knowledge on this topic is limited, but hopefully I can at least point you in the right direction!
From what I understand, when using a Handy with games, you don’t actually use funscript files. The device has to connect with the game in another way so that it can jump around to different sequences depending on where you are in the game.
Making this happen seems somewhat complicated, but many people are at least attempting it. The first place I’d check is here: Easy Device Integration for Games. EDI - Game Selection - beta: IA , Multi-Channel [11/2025]
If you’re specifically trying to make a Flash game sync with toys, I’ve played around a little with this program and it’s not too hard to learn the basics: Flash Toy Sync - Sync sex toys to flash games
And of course, if you have any interest in furry porn rhythm games, this version of Beat Banger that I wrote a tutorial for has a mod to sync with toys built right in! Beat Bangers Furry Faphero Game Device-Compatible Version (Download and Tutorial for Windows) [Furry]
Hopefully this info will at least give you a starting point and maybe encourage more experienced users to correct me or add detail.