In the introduction author Roy Levin, sexy PhD, notes that is the first of its kind, and that until 2006 everything we knew about nipple and breast stimulation came from opinion-based comment. By this I assume Levin meant women shouting More! More! during sex. Only 7.2 percent of women surveyed said that breast stimulation decreased their arousal.

The problem is that nobody really tells men what to do with boobs. I always think of Jon Hamm in Bridesmaids, convinced hes working sexy sorcery on Kristen Wiig while he rubs her boob like its a magic orb. Heres what to do instead:

Leave her bra on for a second.

Bras are really expensive, and to find a bra that works (which is to say, one that makes our breasts look shapely and one to four sizes larger than they actually are) we have to try on about 900 of them. Women go through all this because good bras make us feel sexy and confident, and the more sexy and confident we feel, the better the sex is going to be for all parties involved. We want you to appreciate each bra-and how our boobs look in it-for at least a couple seconds before you tear it off and throw it on the floor.

Compliment them.

Once youre naked with a woman, you want her to feel confident about how her boobs look when theyre bouncing around up there. The boob compliment is a refined art. Some women are really self-conscious about the size of their boobs, so instead of calling them huge, if theyre big (or cute, if theyre small) stay vague: Tell her that her boobs are hot, perfect, or amazing.

Be gentle.

Even when youre fumbling around blindly up there, it feels pretty nice as long as youre being gentle. from the Journal of Sexual Medicine found that touching someones nipples activates their genital sensory cortex, which is the same part of the brain that is activated by touching their clitoris. Some women can even have orgasms . Just dont pinch them or grab a womans nipples unless she asks you to. While nipples arent clitoris-level sensitive, theyre sensitive enough that when something youre doing hurts, it really hurts.

Use your mouth, but sparingly.

As a former infant myself, I suppose I understand why one might want to suck on a nipple. But as a boob-haver I can tell you that theres a very fine line between feeling aroused and feeling like Ive stumbled into some mother roleplay (autonepiophilia). For me that line is crossed as soon as a man starts sucking on, versus licking, my nipples. The first time a man did the former to me I thought, Awww, hes latching, and it was over. Likewise, you dont want to keep your mouth on someones nips for too long. A couple seconds of nipple-licking is hot, but when youre coming up on a minute it starts to get maternal.

Literally playing with boobs is funny, but its not sexy.

I definitely understand the urge to motorboat. If I could motorboat myself, I would. I would do it all the time. It looks so fun. Motorboating falls into a different, non-sexual class of boob-touching. As with honka-honkas, boob bongos, and the like, motorboating is really funny when youre not about to have sex. If gentle touches and light licking activate the genital sensory cortex, motorboating does the opposite of that.

When in doubt, call them boobs.

While it can be endearing when a man has his own term for breasts, during sex you should refer to them as boobs. Every word for breasts is gross (breasts, especially) but boobs is the least gross. I won't call your penis "Little Buddy" if you don't call my boobs "knockers."