Nipple stimulation lights up the same area in the brain as the genitals.
Start with a light touch, and anything goes here. Lips, tongue, a feather, or a small vibrator are just a few ideas.
Trace around the areola before moving onto the nipple and sucking, licking, and even flicking. Blow or use an ice cube for some sexy cool.
If your partner likes it rough, graze the nipple with your teeth. Rougher still? Try nipple clamps.