Not that you're doing anything wrong, have you thought about : https://www.amazon.com/OSPet-Water-Anti-Choking-Dripless-Breeds/dp/B07DPG4T9Z/ref=sr_1_1_sspa?crid=1TJ4PCPKRYMY8&keywords=slow+water+bowl+dogs&qid=1550126294&s=gateway&sprefix=slow+water+%2Caps%2C236&sr=8-1-spons&psc=1
something similar? He'll get frustrated with it and eventually stop snorting the water.