I made this several years ago after we accidentally put my daughter's bendy straw in the dishwasher where the heat unbent the straw.
To use the tool print it out in the highest temperature resistant material you have, at least PETG.
Get the straw hot enough to flex and put one end into one slot of the jig. Bend the straw around the post and then line it up with the exit slot. Wait for the straw to cool or pour cold water over everything.
The straw should hold its shape as long as it doesn't get too hot again.
The author marked this model as their own original creation.