Whether in Philadelphia, Washington, Baltimore, New York or wherever, people primary do jitterbug , west coast swing and lindy at swing dances. Lindy is the most popular and fastest growing dance, but it is more involved than jitterbug. Jitterbug , sometimes called East Coast Swing, is a repeating pattern of 4 steps.
Men start with a left step and the ladies start with a right step.
The woman starts on the slow right. Since you are facing your opposite sex partner, in a sense, each is a mirror-image of the other. Timingwise, both go slow, slow, quick-quick. And the slows correspond to the lefts and rights. Similarly, the women agree to dance as equally out of politeness as anticipation, so asking women to dance at PSDS events is a high percentage move for men.