From the stomach position, both partners can roll over on their sides, still facing the same way, with one leg drawn up. This is called Spoons and is a good starting position. It helps prevent the penetrating partner from going too fast, and allows complete control over penetration. It also brings you closer to your partner so you can judge their reaction to what you're doing. It allows bodily relaxation plus free hands to explore and caress.
Entry is easy and fairly deep though movement is somewhat limited.
Vigorous thrusting is still easy once you get used to the posture. Another popular position is for the male to lie on his back, bracing his cock with your hand and the woman straddles his legs and lowers herself onto the erect penis. Either in a forward or reverse position. Be careful the penis cartilage can be torn or sprained. In this position the person being penetrated has the control as to how much cock actually enters them and at what rate.