1) Always start slow and gentle.
Until you get to know your lover's sensitivity levels, it's best to start slow and gentle. Sensitivity can vary tremendously from woman to woman. For some, merely blowing on a nipple will cause sensory overload, while for others, rough is never enough. Another thing to remember is that breasts vary in their sensitivity at different times of the month.
2) Be a tease.
Try kissing, stroking, and licking your lover's breasts while pointedly avoiding the areola and nipple. If your lover likes direct nipple stimulation, this kind of teasing can be delightfully frustrating. If your lover whimpers, that's a good sign that she wants you to latch on. If your lover doesn't want nipple play, touching the rest of her breast can feel wonderful on its own as well.
3) Don't play favorites.
Remember that your lover has two breasts, so don’t just focus on one. If you're spending a long time on one breast at the expense of the other one, take a trip to the other side. This allows the first one to reset and be more responsive to a range of sensations.
4) Be mostly superficial.
While breasts are packed with sensitive nerve endings, most of the pleasurable sensations come from the surface of the breasts. So while you pinch, stroke, and lick, keep the breasts where they are, and keep your hands and mouth focused on the surface. Remember, breasts are attached to the rest of her body, so don't move the root of the breast or knead too deeply.
5) But don't ignore the rest of her breasts, either.
Although nipples tend to be the center of the attention, the entire breast can yield a bounty of sensation. Try kissing her rib cage on her sides, or explore the crease on the underside of her breast. Also, give some attention to her clavicle, cleavage, and the top of her armpit.
6) Master multi-tasking.
If your lover really enjoys nipple play, try using your lips on one nipple and mimic the motions of your lips on the other with your hand.
7) Play it cool.
Try getting a nipple wet with saliva by licking and sucking, and then blow on it gently. The cool sensation will create delicious tingles.
8) Ask before you bite.
To get an idea of what your lover likes, ask her to help you figure it out. Tell her you're going to bite ever so gently, and then slowly increase the pressure. Ask your lover to tell you when you've reached their limit. This will give you a great sense of what feels good so that you know how much is too much.
9) Some women can have nipple orgasms.
Some women can and do reach orgasm just from nipple stimulation. If this is you or your lover want to try to have one, my article How to Give a Woman a Nipple Orgasm outlines an approach that works.
10) Remember to also pay attention to the rest of her body.
It's easy to get so excited about playing with a pair of breasts that you forget about the rest of her body. Unless you're trying for a nipple orgasm, mix in kisses and caresses elsewhere on your lover's body with your breast play. It will make it even better.
For more specific breast play techniques, see my articles Lesbian Breast and Nipple Play and 5 Lesbian Breast Fondling Techniques. The best thing that you can do for your lover's breasts, though, is appreciate them. That's a turn-on in and of itself.
My book Lesbian Sex Secrets: How to Have Amazing Sex With Another Woman aims to help bi-curious, bisexual, and lesbian women take their sex lives to another level. To give your lover the best sex she’s ever had, starting tonight, click here!