Yes, you can totally have sex during your period after being pregnant. "If you're prone to menstrual cramps and cyst formation during the times of your period, certain positions may be more painful during this time, but it's not dangerous," says Chinn. Your best bet is woman on top or reverse cowgirl, because you have more control over the motion. "Missionary might be more painful because your partner [has more] control over the angle and speed," she says.