It is begging for trouble. Getting to know a woman, touching her is critically important in a relationship. Physical contact at the wrong time can intrude, hinder real understanding, block communication. You learn more about each other by joining your voices in song, by becoming one in music and lyrics and poetry, than by sleeping together. You get a deeper sense of communion by sharing a meal than by sharing a bed.
Physical intimacy implies commitment , responsibility, a sense of permanence.
It is a promise, a contract. The two of you should be fully committed to each other before you seal the bond with lovemaking. A man and a women exchange glances, perhaps smile at each other wistfully. He would like to talk with her. Unfortunately, they are seated in a New York subway car, and strangers just don't approach one another in that setting.