Just a quickie: It's too much fun not to play with stuff. And remember, if you're not having fun in bed, you're doing it wrong. I recently discovered that vibrators are not just for girls (even if they're pink). If you haven't tried holding a slim yet powerful vibe to your boyfriend's "taint" while sucking his dick, neither of you know what you're missing. Try it. He will thank you in new and exciting ways for that one. If you've always wanted to watch a man shiver, shudder, and beg, this is one way to make that happen without really all that much more effort on your part.
This is something you can surprise him with, and in fact, should. If it works well, and you'd like to try inserting something up his bum, you should ask first. Some may find it hot, others objectionable. If you decide to go that route, just remember your basic safety rules -- condoms, disinfection, and nothing that goes in the butt should go near or touch anything else (aside from the ick factor, there's the painful-burning-infection factor).
But to end on a positive note, seriously, if you want to give your man a mind-blowing orgasm, I recommend a bit of dirty talk and foreplay, and then pull out the vibe when he's not looking. A few minutes later, listen to him babble about how amazing you are. This is a good time to mention jewelry.