A passionate night with a lover usually involves a bit more than just making out. Partners enjoy close encounters with each other’s most intimate body parts…and fluids. And yet if your sexual lover forgets to bring their toothbrush with them, after spending the night with them, the thought of them borrowing yours might be disgusting. How do we explain this? Many of the primary sexual stimuli—such as ejaculate, saliva, and sweat—evoke a sense of repulsion in people who are not sexually aroused. So how can we overcome revulsion and enjoy great sex?