i've found that i can cum pretty easly w/ manual simulation after reaching almosst the point of climax with vibration(because it hightens the sensitivity). so possibly, if he used the Hitachi of you for a while and gets you really close you could climax during sex.

We use it either in doggie or a missionary variation, where he's not on top, but kneeling while I'm laying back. That doesn't work too badly.

There's a video "Midori's Guide to Expert Bondage" which has a section where she does a "harness" with silk ties and the hitachi. It's a good demonstration of how to tie it.

For doggy style when I'm holding something (vibrator, dildo, etc) I usually pile up a couple pillows in front of me (at about shoulder height) and rest my upper chest/shoulders on them. I don't know if I'm painting you a very clear picture, but it provides a lot of extra support for me so that I can use a hand and not lose balance or feel uncomfortable. I would try experimenting a little bit with pillows or blankets.

I also wanted to mention that sometimes by using one vibrator consistently to get off your body gets accustomed to that strength. After a while anything less won't cut it. That's why it's a good idea to either vary your vibrators, alternating between two or three, or if you don't want to spend the $ on an array of vibrators then you can just get a single vibrator that has a wide range of speeds. The Hitachi is notoriously intense and also notorious for causing desensitization. You may want to consider getting another vibe to alternate with, one with several speeds and patterns, and try experimenting with it.

My wife likes to use the hitachi when she is on top and leaning back her hands on my legs for suppport. Iam the one who has control of the hitachi so she can control her thrusting. This has worked 100% of the time....