Nipples are bundles of nerve endings. They are one of the various erogenous zones in our body. Touching them would mean stimulating them, which brings immense sexual pleasure. Touching your nipples triggers or shoots sparks in the genital sensory cortex, the part of the brain that also gets stimulated during vaginal and/or clitoral stimulation. Since the same region of the brain is activated when you play with or stimulate your nipples or genitals, and since the brain can’t tell the difference, touching your nipples can feel extremely pleasurable.