Whipped cream can be made ahead and stored in the refrigerator in an airtight container for up to 2 days. Stir it a little since it will have deflated a bit.
The longer you whisk the heavy cream, the stiffer the cream will get. If you want more of a pourable whipped cream with soft peaks that will stir into the drink easier, whisk until it thickens slightly. Make sure to move the handheld milk frother up and down to get air into the cream.