Laughter is another form of reaction. If I don't get carried away, I can stay present to what was behind the initial impulse to laugh, and the movement continues. But if I give in to more laughter, it's pleasant of course, but I've likely already lost the main channel and am now hanging out in some eddy.
Releases of contractions can also become a distraction. If I become totally focused on, for example, the new, deep, fresh breaths of air I can now breathe into my lungs, that's okay, but I lose connection with the original energy and will have to continue next time.