We present a new method (BUBBLY) for detecting expanding components of ionized gas using integral field spectroscopy, showing its capabilities not only in detecting but also in obtaining the key physical parameters of the expanding shells: their expansion velocities and masses. The main advantages are that the detection is performed automatically via software and that we can derive most parameters of the shells, so it is suitable for detailed studies of feedback in nearby galaxies. The software can easily be configured to run on any data cube mapping an emission line over a spatial field. We also present results obtained by running BUBBLY on observations of Hα emission with the Fabry-Perot spectrograph GHαFaS: two sets of spectacular results at widely different spatial scales: the Antennae galaxies show multiple giant bubbles of size ~300pc around the brightest clusters, while inside a region in M33 we find three nested supernova remnants, with which we can study the feedback on the molecular gas surrounding the cluster.