Invest in some good lube, something like Sliquid Sassy booty, or a silicone lube like Better Sex Essentials if you're not going to use any silicone toys. Using plenty of lube--and a good quality lube--can make all the difference.
I totally agree about starting with fingers. One finger at first, a pinky if necessary. Go slow and be patient! Once that one finger is comfortable, move it around. Stimulation from within is the key to relaxing the muscles. When one finger's comfortable, add a second finger, and when he's OK with that, scissor your two fingers. It may take a few minutes--or several weeks--to get to this point, depending. Just be patient and accepting and help him relax and enjoy.
Toys are great. Start small and go slow. I agree about tapered toys and I think glass is just awesome for warm-up and short-term wear. I've also heard good things about metal toys, but they're more expensive. Silicone toys are also good, and are much better than glass for long-term wear if you decide to explore that.
One of my all-time personal favorites is a simple bullet vibe (with a cord, please, so it doesn't get lost inside him!). There are many to choose from; I have this one and it works great: link
It's small, stimulates the prostate nicely, and sometimes it's still all I want.
Finally, I like to give myself a quick enema before anal play, nothing major, just a few rinses with something like this: link
(Again, there are several other good options.) Follow it up by applying some lube and you will be "go" for anal play.