Get a plastic milk bottle. Cut some off. Wrap it around the teat and leave it a bit long.Then wrap that in black tape .
Put a hole through the extra milk bottle and secure to bottle with elastic string.
Easy peasy and it works.
You’re gonna have to show us a pic as I’m struggling to picture this.
I was wondering yesterday, while spitting out bits of mud, whether anyone sells a rubberised “lid” to pop on top of the nozzles of your existing bottles.
Could sell a pack of a few in slightly different sizings to account for varying nozzle dimensions.