When I shave the upper lip I do not go against the grain I go with the grain and slightly across the grain. When doing this on the upper lip I take care of the heal of the blade, because that is usually the peice that I nick myself with if I indeed I do nick myself. Practice good razor control. Know where that razor is going to touch you when you move it. Im not saying do not go against the grain, but that is usually where I see people cut the corner of thier mouths. I do not need to go against the grain in this area YMMV. I also like to take economy strokes, small strokes, in that area because it is confined and there is alot of area to cut yourself.