Too much pressure may rip the head. Another way to seat a head is to hold the rim and turn it back and forth a few times, like driving the Seasame St bus. This doesn't work as well as shown above, but it's better than nothing. Muffling the kick drum gives the drum a punchier sound. The amount of muffling may also differ the drums sound.
People use many different things to muffle the ring of a kick drum.
It is a good idea to muffle both heads, and easiest to muffle both using the same item. I use a rolled up towel. Roll the towel to make a snake. Place it inside the drum. Simple, light, and effective.