I shave mine using a manual shaver (not electric) and just water in the shower, no soap or cream. Never have bumps or itchiness. I'm no expert, but maybe you're shaving too hard? Don't press on your skin, just touch the razor to it and lightly brush along the surface.
A light lotion might help with the itchiness, if shaving more lightly doesn't. Chances are the itchiness is from dry skin. Shaving off the outermost surface takes away what little protective oil is there and just aggravates the dryness.
Also think about drinking more water, which helps dry skin in general.