Food and flavors are integral to our existence in the world. Nonetheless, taste remains an under-explored sense in interaction design. We present Füpop, a technical platform for delivering in-mouth flavors that leverages advances in electronics and molecular gastronomy. Füpop comprises a fully edible pouch placed inside the mouth against a cheek that programmatically releases different flavors when wirelessly triggered by a focused ultrasound transducer from outside the cheek. Füpop does not interfere with activities such as chewing and drinking, and its electronics may be integrated into devices already used near the cheek, such as mobile phones, audio headphones, and head-mounted displays. Füpop’s flavors are from “real foods,” not ones imitated with synthetic reagents, providing authentic, nutritive flavors. We envision that with Füpop, flavors may be synced to music, a phone call, or events in virtual reality to enhance a user’s experience of their food and the world.