Drilling a new hole in the lid of a glass teapot
A new, larger hole in this lid would improve air flow for a smoother pour. I used a Dremel tool model 4000 and the glass drilling bit number 662, with included drilling oil. Note the technique used for drilling glass: short and light compressions with breaks in between, adding a drop of oil every few times.
Pouring is now much smoother thanks to the modification.