Will sex harm the baby?
NO! The mucus plug in the cervix protects the baby from infection. The amniotic sac also well cushions the baby. If the baby reacts its only because of your increased heartbeat. He doesn't know what's happening and the gentle waves it feels during orgasm will relax the baby . There may be times however that you may be advised against having sex and this should be discussed with your doctor. In a normal pregnancy however its all good. Go for it.
Will it feel as good?
That depends on the woman. Some women find sex even more enjoyable while pregnant. You don't have to worry about getting pregnant for one thing! Some women can experience cramps or a feeling of fullness. While some women feel sexy others are too tired or nauseated to be in the mood. this usually passes after you enter the second trimester.
Oral Sex
normal oral sex won't harm you or your baby and many consider it a nice substitute if intercourse is deemed too risky
What are the most comfortable positions?
Lie sideways. Having your partner on top demands increasingly creative gymnastics as your belly grows. But lying partly sideways allows your partner to keep most of his weight off your stomache.
Use the bed as a prop. Your tummy isn't an obstacle if you lie on your back at the side or foot of the bed with your knees bent, and your bottom and feet perched at the edge of the mattress. Your partner can either kneel or stand in front of you.
Lie side-by-side in the spoon position, which allows for only shallow penetration. Deep thrusts can become uncomfortable as the months pass.
Get on top of your partner. It puts no weight on your abdomen and allows you to control the depth of penetration.
Enter from a sitting position, which also puts no weight on the uterus. Try sitting on your partner's lap as he sits on a chair.