OSR2 DIY Tilt Question

I’m looking at synchronized servo physics such as

https://twitter.com/buttplugio/status/1256682208938438662

The 2 main servos run synchronously to lift the arm, and when the servos asyncs it provides a bit of tilt. Where does the tilt come from, seems most pieces are rigid and don’t allow much bending.

Im trying to build the most basic OSR2 possible, think 2 servos and a controller.

Its real clear that they lift the fl synchronized,
however if the servos run in opposite directions im having trouble determining, or imagining
how the ‘bending’ is happening. The arms look rigid, but if I use say metal arms, would it still bend or
tilt the same way? Is the rubber grommets what allow the bending? How much can the servos deviate from each other? If they both ran a random stroking pattern independently would that cause problems?

The 2 arms connected to the servos aren’t screwed tightly to the part holding the fleshlight.
There’s a screw for each arm sticking about 1cm out of it and the arms have holes, which are bigger than that screw (not the screw-head though) so they have enough wiggle room to move in separate directions without having to bend.
The rubber grommets are there so everything holds together a little tighter and doesn’t make as much noise when switching directions.

That’s also why there’s a 3rd arm on one side sitting above the other arm. So that the fleshlight doesn’t just tip over, since the 2 arms alone don’t prevent it from rotating back and forward.