When pouring a standard glass of soda (usually Diet Pepsi), whether on ice or not, the soda fizzes a bit and quickly dies down. When pouring soda over ice cream (again, usually Diet Pepsi but also Root Beer) the soda is particularly fizzy and "foamy" and takes significantly longer to die down.
Why is this? Is there anything I can do to help the soda to not foam up so much or to die down more quickly? (Not interested in flat soda)