Some of us on the forum use cotton swabs on the little sticks to draw with as we start a new painting. Basically it just involves painting in your background color and then using a cotton swab to draw into the wet paint. I often use this for a still life or a landscape. Swabs are great for putting in an outline, front/back edge of a table, general area of a cluster of grapes, flowers, mountain ranges, larger trees, etc.
It is generally recommended to use the cheaper cotton swabs you might find at a Dollar General store for example. Why? Because they are harder and do not shed bits of cotton into the wet paint compared to the fluffy softer cotton swabs.
However, my wife just introduced me to the new Q-tips Precision Tips. I tried them this morning and they work great! They are stiff (no shedding) and have a tapered tip for drawing even finer lines or points when needed. http://www.qtips.com/product/detail/115035/precision-tips
The great thing about doing a drawing this way is that if you make a mistake or want to experiment a bit by placing things in different locations, all you have to do to change something is repaint the area with more background color and redo it! It really frees you up to try something new and is quick and easy to do.
While not a great drawing technique for all compositions, elements, some types of painting or when great or precise detail is needed, it is certainly worth a try...especially now that we have both rounded tips and tapered tips.