Summary

I often buy wine in gallon bottles, and it's difficult to pour directly from the large bottle. So, I like to transfer some to a smaller, empty wine bottle.

This funnel has an integrated vent and a splash shield. I've made others and this is the right way to make a funnel, imho. The vent is somewhat difficult to design, but it is worth the effort.
It's amazing how fast you can pour without blocking and overflowing it when there is a good air vent.

The funnel's spout is 0.69 inches (17.5 mm) diameter, to fit the narrow neck of a bottle. The body is only about 2 inches wide. It seems small, but print one, and hold it under a faucet to see how fast it can funnel water.

44 minutes, 16 grams ABS using Afinia default settings. There is practically no support when oriented as shown.
Metric and SAE files provided.

Printing notes-
The air tube must be liquid-tight. If liquid seeps through the side of the tube, it cannot exhaust air, and is useless.

I suggest using a slow speed, or a "fine quality" print setting, and / or fan cooling to get the highest quality possible. Thin layers may help, but I wouldn't know.

Plug one end and blow in the other. The tube should be (virtually) air tight.