I have been using this technique since I started masturbating and It has never failed me.
I first start out reading a couple sex stories it helps to get me wet,or i watch a few pornos. Now after or while im watching or reading I reach down and dip my hands bellow and start fingering myself.
after im good and wet I ball up some covers and maybe get a pillow or two undernieth me i begin to gently hump the pillow while i think of the sex scenes and how the touch would feel against my skin.
I reach bellow and sometimes taste myself and if im really horny i pinch and pull at my nipples.