We have been very keen to make sure my wife gets good stimulation during pegging and came to the conclusion after much experimentation that the Nexus/Feeldoe/Share type double-ended dildos used in conjunction with a harness were the way to go.
We use a harness because none of these dildos seems to have the rigidity to work without support. A harness ensures that the saddle of the toy remains in good contact with the clit whatever the angle and allows the wearer to enjoy vigorous thrusting without the fear that the bulb will just pop out.
Lots of people say that these dildos are too short for pegging and we would have agreed with that - we used to use cock-extension sleeves to increase the length of the toys and this may be of help for some. However, we found that with the right harness the Share and Share XL dildos can be made to project further forward and have enough reach for us to use them in our favourite face-to-face position without having to resort to the extension. This is good as a double dildo with a 3 inch extension on it looks like it contravenes some arms limitation treaties