While just about any sexual position that can be done with a penis can be done with a strap-on (as well as others), there's a few in particular that should be mentioned.

A woman pegging a man doggy-style with a 4-strap harness and dildo, using the corner of the bed to adjust the height to that most comfortable for penetration

• Doggy style- Doggy style is popular, as it's simple, easy, and allows deep thrusting. The receptive partner kneels down with his or her face against the bed (or other surface), and is penetrated from behind. This position works well for both vaginal and anal penetration, and allows deep, smooth strokes, however it sometimes stimulates the prostate less than other positions during pegging.

• Missionary- The missionary position is also popular, and allows both partners to cuddle, see each other, kiss, or perform other activities during intercourse. When used for anal penetration, a pillow or other object (specially made foam cushions are available for this purpose, but their effectiveness over a pillow or two is debatable) placed under the buttocks of the receiver will elevate the anus to a comfortable position and angle.

• Bent over- Usually used for pegging, the man stands or kneels while leaning forwards, supported by the bed, chair, wall, or other object. Similar to doggy style, he is then penetrated from behind. This position angles the dildo such that it typically strokes firmly across his prostate, and for some men can lead to an anal orgasm much more effectively.