Comfortable bondage positions for sex

In addition to the clit jewellery I mentioned in my other post I'd also like to buy my wife some bondage ropes.

To sell this idea to her I need to be able to tie her up in a reasonable comfortable position and then give her a good fucking.

Is there any resource out there on the Internet (pics etc.) of practical positions. Most of the porn stuff is actually quite uncomfortable to maintain. I need to find some decent fuckable positions for her so she likes the idea and we can then progress further.

Any advice appreciated.