You would be amazed at what people are willing to do when someone opens the door and says it's ok to try something new or something taboo.
When I first met my husband, he thought sex was just that - sex. I kept introducing new topics of discussion and gauging his reaction to my ideas. Now? His fantasies far surpass my own and I have to run to catch up sometimes. If it's taboo or a fetish, we've talked about it and/or done it to some degree.
Given you are the one wanting to try new things, it would be beneficial to have researched all of the high points and low points to the activity and have answers readily available for questions he may have. If he asks you something about this and you don't have the answer, that's ok too. Just explain that you don't know but it would mean a lot to you if you could discover the answer together.
Be patient. It may take two or three or thirty discussions before he agrees to do something you want. He has to be comfortable with the idea and it may seem like it's taking forever, just remember you wouldn't want to be rushed in a similar situation. (Watching porn with the activity of your choice as the theme is a really good way to get things pumped.) Good luck!