Sometimes, when reading some Buddhist sutras, it happens that I feel strong vibrating sensations all over the body. On such occasions I 'know' that the best I can do is stopping the reading and practice vipassana. I wonder if this is 'normal'.
That's cool you pointed that out. The Buddha and many masters of course would say that you are practicing learning-yoga where through absorbing the expressions of anyone with cultivaton attainment, you too come closer to what they experienced. Some masters even got enlightened when they heard a particular thing from a master and it caused them to look directly at "Who is the one listening?" and they found out their True Self.
Whenever I noticed this sensation in my body (very frequently) I actually get the same thought... that vipassana is the direct road... that vipassana is great and awesome and the meta-physical life is so simple, just pure awareness, and I am grateful that it is so. I also feel my body vibrating, especially my legs sometimes my body.
I tell myself I should get to practice but due to the ideas and good feeling I oftentimes keep reading until my time is up waiting till my scheduled time to practice.. :-/
I am convinced that this is the energy channels opening and that instead of sitting like a dead duck when such an opportune moment comes, one should meditate for 10 or 20 minutes because Master Nan, one of my late teachers, himself said that we cannot attain samadhi at any time we choose, there are certain opportune moments that we should seize!
I should definitely stop myself and practice what I learn much much more like you have thought, I think that is the wise choice of action reccommended by my teachers, especially William Bodri who states that you have to mix up theory with practice, either one alone will get you nowhere.