Takeaway cup plug

I went through the drive-through the other day and they stuck one of these things in the spout of my takeaway cup to stop the coffee spilling out as i drove. Never seen them before but thought it was a good idea. Here's my version of it. I've added a hole in the top so you can carry it around on a string or something.

Haven't printed it up yet, but would recommend some sort of food-safe filament.