IoT devices are in general considered to be straightforward to use. However, we find that there are a number of situations where the usability becomes poor. The situations include but not limited to the followings: 1) when initializing an IoT device, 2) when trying to control an IoT device which is initialized by another person, and 3) when trying to control an IoT device out of many of the same type. We tackle these situations by proposing a new association-free communication method, QuickTalk. QuickTalk lets a user device such as a smartphone pinpoint and activate an IoT device with the help of an IR transmitter and communicate with the pinpointed IoT device through the broadcast channel of WiFi without a conventional association process. This nature, QuickTalk allows a user device to immediately give a command to a specific IoT device in proximity even when the IoT device is uninitialized, unassociated with the control interface of the user, or associated but visually indistinguishable from others of the same kind. Our experiments of QuickTalk implemented on Raspberry Pi 2 devices show that QuickTalk does its job quickly and intuitively. The end-to-end delay of QuickTalk for transmitting an IoT command is on average about 0.74 seconds, and is upper bounded by 2.5 seconds. We further confirm that even when an IoT device has ongoing data sessions with other devices, which disturb the broadcast channel, QuickTalk can still reliably communicate with the IoT device at the cost of minor throughput degradation.