His and Her Bonding

This interview with Daniel Amen, author of the new book Sex on the Brain: 12 Lessons to Enhance Your Love Life," has some great tips on how to work on improving your sex life before you get into bed.

He also explains the differences in men's and women's oxytocin responses:

In women, holding hands, kind looks, doing something special for someone our partner loves, are all ways to increase oxytocin. In turn, it increases their bonding to their partner. For men, an orgasm actually increases oxytocin, up to 500 percent. So men need orgasm to become more bonded and connected, while women need touch and talking in order to get to the place of wanting to help their partner have an orgasm.

However, I don't believe he's quite correct. The brains of men, too, release oxytocin in  social and intimate situations.  That's why, in the trust studies done by Paul Zak and others, sniffing oxytocin increased trusting behavior. But men don't feel oxytocin's effects as strongly, nor do they last as long, because testosterone mutes oxytocin's effect, while estrogen increases it.