In some types of concentration practice, there is what is called concentration phenomena and sometimes this concentration phenomena develops through deep concentration. However, this is not the purpose of meditation, just to feel this concentration phenomena. In the mindfulness practice, we want to observe it objectively, as we do everything else, because we're trying to understand the reality of things and, especially, see the impermanence, the unsatisfactoriness of it and how it's beyond our power to control. So in this instance, in the insight meditation practice, we would just note it objectively using mindfulness, mental noting of whatever happens. Perhaps you feel big. Then you would just say, "Feeling big, feeling big." We just note it objectively so we can go beyond just feeling concentration phenomena and start to understand the reality of things, get insight into the impermanence of things, and go beyond it.
An analogy I like to use with concentration phenomena is that we're going along a road in a bus and it's very hot. It's not an air-conditioned bus, and we're going along and it's kind of difficult. Then we get to a nice, air-conditioned bus stop. We get out, we go have a nice drink and it's lovely inside. It's relaxing. Then, when it's time to get back on the bus, we don't want to get back on the bus because we're having such a nice time in the air-conditioned stop. Don't get stuck in the stop! If the body spins, just try to note it objectively -- "spinning, spinning" -- and then you'll start to see how things change. They arise and they pass. They're not me, they're not mine. Then the meditation advances more, and you get more insight into how things are.