Down to ~27 meters, there is also nothing special when freediving, assuming that you took the fullest possible breath before diving. This is because the water pressure compresses your chest, but it is within the normal excursion limits, i.e., it would compress to the same degree if you fully exhale on dry land, so it feels like something that commonly happens.
Below that, it feels like something tries to squeeze you softly. You can try to emulate this feeling on dry land by forcefully exhaling everything that you can plus a bit more with arms down, closing the glottis, and then lifting your arms up.
Down to ~27 meters, there is also nothing special when freediving, assuming that you took the fullest possible breath before diving. This is because the water pressure compresses your chest, but it is within the normal excursion limits, i.e., it would compress to the same degree if you fully exhale on dry land, so it feels like something that commonly happens.
Below that, it feels like something tries to squeeze you softly. You can try to emulate this feeling on dry land by forcefully exhaling everything that you can plus a bit more with arms down, closing the glottis, and then lifting your arms up.