The sensitivity of the nipples varies greatly from person to person. Some like you to be very gentle, while others love it when you are a little bit rough. Ask what your lover wants or pay attention to the body language.
Encircle the nipple with your mouth, shielding your teeth with your lips. Move your tongue upwards, pushing the nipple against the roof of your mouth. Roll the nipple softly back and forth, discovering how to milk it in such a way that your lover enjoys it.
Encircle your teeth with your lips and grasp the nipple between your lips, moving it up en down by moving your jaw. The nipple rolls around your curved lips.
Take the nipple between your teeth and pull gently or nibble.
Use just your tongue to stimulate the nipple, but not the area surrounding it.
Kiss the nipple after you had a warm drink or when you have an ice cube in your mouth.