Mano po may be polite in Phil but I can`t think of any English families that do it.
Touching their hand onto your forehead and it`s significance can soon be wiped out if you eat and talk with your mouth full so i`d advise against doing that.
Also shelve any plans to try sucking any bits of food through your teeth after you`ve eaten. If your uncomfortable take a toothbrush or floss with you and visit their toilet to clean your mouth.
And if I didn`t know i`d say from your writing that your English it`s that good.
Good luck, i`m sure you`ll get on just fine.