well there might be a spray you can use.

But printing a thin cube with a soft flexible filament is going to be tricky even on a non-bowden printer.

If you go slow enough it might work - but I wouldn't like to put money on it.

A quick look shows various rubber sprays are available, here's a clear one: https://www.amazon.com/Rust-Oleum-26...1581040&sr=8-4

That's probably your best bet.