The impact of flavored ENDS use among adolescents on daily use occasions and number of puffs, and next day intentions and willingness to vape

•This is one of the first EMA studies on measuring ENDS use among adolescents.•Vaping tobacco flavors increases same day number of use occasions and total puffs.•Vaping fruit flavors increases same day total number of puffs.•Flavor appeal increases same day use occasions, number of puffs, and intentions.•Results support regulatory efforts to restrict the sale of flavored ENDS products.