Your finger is a talented probe that simultaneously gives and receive sensory input. We actually have many senses of touch. Light touch, pressure, tickle, heat and cold, vibration, even pain—they’re all distinct signals which travel through separate micro-sensors and nerves, and they concentrate in different parts of the body.
Next to genitals, the nipples run a close second to being the most erotic zone on the human body. Some women can even orgasm just from nipple stimulation alone, while others see no erotic value in it at all. This is because these tiny nubs of delight are packed with a network of nerves, and according to the Journal of Sexual Medicine, Vol 8, 2001, researchers say that the sensation we get from the stimulation of the nipples travels to the same part of the brain as sensations from stimulation of the vagina, clitoris, and cervix